diff --git a/test/parallel/test-buffer-fakes.js b/test/parallel/test-buffer-fakes.js
index 5804cbba30..1a1d9c0c49 100644
--- a/test/parallel/test-buffer-fakes.js
+++ b/test/parallel/test-buffer-fakes.js
@@ -3,7 +3,6 @@
 require('../common');
 const assert = require('assert');
 const Buffer = require('buffer').Buffer;
-const Bp = Buffer.prototype;
 
 function FakeBuffer() { }
 FakeBuffer.__proto__ = Buffer;
diff --git a/test/parallel/test-child-process-exec-buffer.js b/test/parallel/test-child-process-exec-buffer.js
index b9727f0c63..a381af9631 100644
--- a/test/parallel/test-child-process-exec-buffer.js
+++ b/test/parallel/test-child-process-exec-buffer.js
@@ -18,7 +18,7 @@ exec('echo ' + str, function(err, stdout, stderr) {
 });
 
 // no encoding (Buffers expected)
-var child = exec('echo ' + str, {
+exec('echo ' + str, {
   encoding: null
 }, function(err, stdout, stderr) {
   assert.ok(stdout instanceof Buffer, 'Expected stdout to be a Buffer');
diff --git a/test/parallel/test-cluster-http-pipe.js b/test/parallel/test-cluster-http-pipe.js
index 4c6dee347b..cb9b090f08 100644
--- a/test/parallel/test-cluster-http-pipe.js
+++ b/test/parallel/test-cluster-http-pipe.js
@@ -34,7 +34,6 @@ http.createServer(function(req, res) {
   res.writeHead(200);
   res.end('OK');
 }).listen(common.PIPE, function() {
-  var self = this;
   http.get({ socketPath: common.PIPE, path: '/' }, function(res) {
     res.resume();
     res.on('end', function(err) {
diff --git a/test/parallel/test-crypto-binary-default.js b/test/parallel/test-crypto-binary-default.js
index 806f5de18b..c4b8990beb 100644
--- a/test/parallel/test-crypto-binary-default.js
+++ b/test/parallel/test-crypto-binary-default.js
@@ -20,7 +20,6 @@ var fs = require('fs');
 var path = require('path');
 
 // Test Certificates
-var caPem = fs.readFileSync(common.fixturesDir + '/test_ca.pem', 'ascii');
 var certPem = fs.readFileSync(common.fixturesDir + '/test_cert.pem', 'ascii');
 var certPfx = fs.readFileSync(common.fixturesDir + '/test_cert.pfx');
 var keyPem = fs.readFileSync(common.fixturesDir + '/test_key.pem', 'ascii');
diff --git a/test/parallel/test-debug-signal-cluster.js b/test/parallel/test-debug-signal-cluster.js
index 6572ef50af..7a950458b8 100644
--- a/test/parallel/test-debug-signal-cluster.js
+++ b/test/parallel/test-debug-signal-cluster.js
@@ -10,7 +10,6 @@ var options = { stdio: ['inherit', 'inherit', 'pipe', 'ipc'] };
 var child = spawn(process.execPath, args, options);
 
 var outputLines = [];
-var outputTimerId;
 var waitingForDebuggers = false;
 
 var pids = null;
diff --git a/test/parallel/test-dgram-error-message-address.js b/test/parallel/test-dgram-error-message-address.js
index e307a23e24..005695654f 100644
--- a/test/parallel/test-dgram-error-message-address.js
+++ b/test/parallel/test-dgram-error-message-address.js
@@ -20,7 +20,6 @@ socket_ipv4.bind(common.PORT, '1.1.1.1');
 
 // IPv6 Test
 var socket_ipv6 = dgram.createSocket('udp6');
-var family_ipv6 = 'IPv6';
 
 socket_ipv6.on('listening', common.fail);
 
diff --git a/test/parallel/test-dgram-pingpong.js b/test/parallel/test-dgram-pingpong.js
index 29ab92757b..883085a9cd 100644
--- a/test/parallel/test-dgram-pingpong.js
+++ b/test/parallel/test-dgram-pingpong.js
@@ -11,7 +11,6 @@ function pingPongTest(port, host) {
   var callbacks = 0;
   var N = 500;
   var count = 0;
-  var sent_final_ping = false;
 
   var server = dgram.createSocket('udp4', function(msg, rinfo) {
     if (debug) console.log('server got: ' + msg +
@@ -48,7 +47,6 @@ function pingPongTest(port, host) {
       if (count < N) {
         client.send(buf, 0, buf.length, port, 'localhost');
       } else {
-        sent_final_ping = true;
         client.send(buf, 0, buf.length, port, 'localhost', function() {
           client.close();
         });
diff --git a/test/parallel/test-domain-http-server.js b/test/parallel/test-domain-http-server.js
index 99dbf413e3..37dbc30f42 100644
--- a/test/parallel/test-domain-http-server.js
+++ b/test/parallel/test-domain-http-server.js
@@ -9,7 +9,6 @@ objects.baz.asdf = objects;
 
 var serverCaught = 0;
 var clientCaught = 0;
-var disposeEmit = 0;
 
 var server = http.createServer(function(req, res) {
   var dom = domain.create();
diff --git a/test/parallel/test-domain-implicit-fs.js b/test/parallel/test-domain-implicit-fs.js
index f35647b525..f2d5c3800b 100644
--- a/test/parallel/test-domain-implicit-fs.js
+++ b/test/parallel/test-domain-implicit-fs.js
@@ -9,7 +9,6 @@ var caught = 0;
 var expectCaught = 1;
 
 var d = new domain.Domain();
-var e = new events.EventEmitter();
 
 d.on('error', function(er) {
   console.error('caught', er);
diff --git a/test/parallel/test-domain-uncaught-exception.js b/test/parallel/test-domain-uncaught-exception.js
index 8792eb1ce5..35632dbf53 100644
--- a/test/parallel/test-domain-uncaught-exception.js
+++ b/test/parallel/test-domain-uncaught-exception.js
@@ -13,8 +13,6 @@ const assert = require('assert');
 const domain = require('domain');
 const child_process = require('child_process');
 
-const uncaughtExceptions = {};
-
 const tests = [];
 
 function test1() {
diff --git a/test/parallel/test-domain-with-abort-on-uncaught-exception.js b/test/parallel/test-domain-with-abort-on-uncaught-exception.js
index 1c4c7cd808..55133ba673 100644
--- a/test/parallel/test-domain-with-abort-on-uncaught-exception.js
+++ b/test/parallel/test-domain-with-abort-on-uncaught-exception.js
@@ -31,7 +31,6 @@ const domainErrHandlerExMessage = 'exception from domain error handler';
 if (process.argv[2] === 'child') {
   var domain = require('domain');
   var d = domain.create();
-  var triggeredProcessUncaughtException = false;
 
   process.on('uncaughtException', function onUncaughtException() {
     // The process' uncaughtException event must not be emitted when
@@ -116,17 +115,7 @@ if (process.argv[2] === 'child') {
     var child = exec(cmdToExec);
 
     if (child) {
-      var childTriggeredOnUncaughtExceptionHandler = false;
-      child.on('message', function onChildMsg(msg) {
-        if (msg === 'triggeredProcessUncaughtEx') {
-          childTriggeredOnUncaughtExceptionHandler = true;
-        }
-      });
-
       child.on('exit', function onChildExited(exitCode, signal) {
-        var expectedExitCodes;
-        var expectedSignals;
-
         // When throwing errors from the top-level domain error handler
         // outside of a try/catch block, the process should not exit gracefully
         if (!options.useTryCatch && options.throwInDomainErrHandler) {
diff --git a/test/parallel/test-dsa-fips-invalid-key.js b/test/parallel/test-dsa-fips-invalid-key.js
index 0b5773411e..2d30ef6891 100644
--- a/test/parallel/test-dsa-fips-invalid-key.js
+++ b/test/parallel/test-dsa-fips-invalid-key.js
@@ -12,8 +12,6 @@ var fs = require('fs');
 
 var input = 'hello';
 
-var dsapub = fs.readFileSync(common.fixturesDir +
-                             '/keys/dsa_public_1025.pem');
 var dsapri = fs.readFileSync(common.fixturesDir +
                              '/keys/dsa_private_1025.pem');
 var sign = crypto.createSign('DSS1');
diff --git a/test/parallel/test-eval.js b/test/parallel/test-eval.js
index d3a83fbd5a..59b5d1a240 100644
--- a/test/parallel/test-eval.js
+++ b/test/parallel/test-eval.js
@@ -10,7 +10,7 @@ var error_count = 0;
 var cmd = ['"' + process.execPath + '"', '-e', '"console.error(process.argv)"',
            'foo', 'bar'].join(' ');
 var expected = util.format([process.execPath, 'foo', 'bar']) + '\n';
-var child = exec(cmd, function(err, stdout, stderr) {
+exec(cmd, function(err, stdout, stderr) {
   if (err) {
     console.log(err.toString());
     ++error_count;
diff --git a/test/parallel/test-event-emitter-remove-listeners.js b/test/parallel/test-event-emitter-remove-listeners.js
index 8993aadf51..396979a923 100644
--- a/test/parallel/test-event-emitter-remove-listeners.js
+++ b/test/parallel/test-event-emitter-remove-listeners.js
@@ -15,11 +15,6 @@ function listener2() {
   count++;
 }
 
-function listener3() {
-  console.log('listener3');
-  count++;
-}
-
 function remove1() {
   assert(0);
 }
diff --git a/test/parallel/test-file-write-stream3.js b/test/parallel/test-file-write-stream3.js
index ca43239652..c9473c26dd 100644
--- a/test/parallel/test-file-write-stream3.js
+++ b/test/parallel/test-file-write-stream3.js
@@ -124,7 +124,7 @@ function run_test_2() {
 
 
 function run_test_3() {
-  var file, buffer, options;
+  var file, options;
 
   var data = '\u2026\u2026',    // 3 bytes * 2 = 6 bytes in UTF-8
       fileData;
@@ -167,7 +167,7 @@ function run_test_3() {
 
 
 function run_test_4() {
-  var file, options;
+  var options;
 
   options = { start: -5,
               flags: 'r+' };
diff --git a/test/parallel/test-fs-open-flags.js b/test/parallel/test-fs-open-flags.js
index b53a823603..667abb8176 100644
--- a/test/parallel/test-fs-open-flags.js
+++ b/test/parallel/test-fs-open-flags.js
@@ -7,14 +7,9 @@ var fs = require('fs');
 
 var O_APPEND = constants.O_APPEND || 0;
 var O_CREAT = constants.O_CREAT || 0;
-var O_DIRECTORY = constants.O_DIRECTORY || 0;
 var O_EXCL = constants.O_EXCL || 0;
-var O_NOCTTY = constants.O_NOCTTY || 0;
-var O_NOFOLLOW = constants.O_NOFOLLOW || 0;
 var O_RDONLY = constants.O_RDONLY || 0;
 var O_RDWR = constants.O_RDWR || 0;
-var O_SYMLINK = constants.O_SYMLINK || 0;
-var O_SYNC = constants.O_SYNC || 0;
 var O_TRUNC = constants.O_TRUNC || 0;
 var O_WRONLY = constants.O_WRONLY || 0;
 
diff --git a/test/parallel/test-fs-open.js b/test/parallel/test-fs-open.js
index 0a069b9a0b..0818f2b7f6 100644
--- a/test/parallel/test-fs-open.js
+++ b/test/parallel/test-fs-open.js
@@ -1,6 +1,5 @@
 'use strict';
 require('../common');
-var constants = require('constants');
 var assert = require('assert');
 var fs = require('fs');
 
diff --git a/test/parallel/test-fs-read-buffer-tostring-fail.js b/test/parallel/test-fs-read-buffer-tostring-fail.js
index 4299614dc5..1276390aef 100644
--- a/test/parallel/test-fs-read-buffer-tostring-fail.js
+++ b/test/parallel/test-fs-read-buffer-tostring-fail.js
@@ -6,7 +6,6 @@ const fs = require('fs');
 const path = require('path');
 const Buffer = require('buffer').Buffer;
 const kStringMaxLength = process.binding('buffer').kStringMaxLength;
-const kMaxLength = process.binding('buffer').kMaxLength;
 
 var fd;
 
diff --git a/test/parallel/test-fs-utimes.js b/test/parallel/test-fs-utimes.js
index 2ad6cea437..5d5cb40ec1 100644
--- a/test/parallel/test-fs-utimes.js
+++ b/test/parallel/test-fs-utimes.js
@@ -48,7 +48,7 @@ function expect_ok(syscall, resource, err, atime, mtime) {
 // would be even better though (node doesn't have such functionality yet)
 function runTest(atime, mtime, callback) {
 
-  var fd, err;
+  var fd;
   //
   // test synchronized code paths, these functions throw on failure
   //
diff --git a/test/parallel/test-fs-write-file-sync.js b/test/parallel/test-fs-write-file-sync.js
index 72c0a2b19b..7ae9e122ca 100644
--- a/test/parallel/test-fs-write-file-sync.js
+++ b/test/parallel/test-fs-write-file-sync.js
@@ -15,7 +15,7 @@ fs._closeSync = fs.closeSync;
 fs.closeSync = closeSync;
 
 // Reset the umask for testing
-var mask = process.umask(0o000);
+process.umask(0o000);
 
 // On Windows chmod is only able to manipulate read-only bit. Test if creating
 // the file in read-only mode works.
diff --git a/test/parallel/test-preload.js b/test/parallel/test-preload.js
index c1d92c7818..f30ad1d218 100644
--- a/test/parallel/test-preload.js
+++ b/test/parallel/test-preload.js
@@ -82,7 +82,6 @@ child_process.exec(nodeBinary + ' '
   });
 
 // https://github.com/nodejs/node/issues/1691
-var originalCwd = process.cwd();
 process.chdir(path.join(__dirname, '../fixtures/'));
 child_process.exec(nodeBinary + ' '
   + '--expose_debug_as=v8debug '
diff --git a/test/parallel/test-promises-unhandled-rejections.js b/test/parallel/test-promises-unhandled-rejections.js
index e229bada3a..5e7739daa5 100644
--- a/test/parallel/test-promises-unhandled-rejections.js
+++ b/test/parallel/test-promises-unhandled-rejections.js
@@ -185,12 +185,11 @@ asyncTest('When re-throwing new errors in a promise catch, only the' +
 asyncTest('Test params of unhandledRejection for a synchronously-rejected' +
           'promise', function(done) {
   var e = new Error();
-  var e2 = new Error();
   onUnhandledSucceed(done, function(reason, promise) {
     assert.strictEqual(e, reason);
     assert.strictEqual(promise, promise);
   });
-  var promise = Promise.reject(e);
+  Promise.reject(e);
 });
 
 asyncTest('When re-throwing new errors in a promise catch, only the ' +
@@ -629,7 +628,7 @@ asyncTest('Promise unhandledRejection handler does not interfere with domain' +
       assert.strictEqual(domainReceivedError, domainError);
       d.dispose();
     });
-    var a = Promise.reject(e);
+    Promise.reject(e);
     process.nextTick(function() {
       throw domainError;
     });
diff --git a/test/parallel/test-readline-undefined-columns.js b/test/parallel/test-readline-undefined-columns.js
index 73945af8bc..24f138f46b 100644
--- a/test/parallel/test-readline-undefined-columns.js
+++ b/test/parallel/test-readline-undefined-columns.js
@@ -11,7 +11,7 @@ const readline = require('readline');
 const iStream = new PassThrough();
 const oStream = new PassThrough();
 
-const rli = readline.createInterface({
+readline.createInterface({
   terminal: true,
   input: iStream,
   output: oStream,
diff --git a/test/parallel/test-regress-GH-4256.js b/test/parallel/test-regress-GH-4256.js
index 1a4a78b3c0..a312fb277f 100644
--- a/test/parallel/test-regress-GH-4256.js
+++ b/test/parallel/test-regress-GH-4256.js
@@ -1,6 +1,6 @@
 'use strict';
 require('../common');
 process.domain = null;
-var timer = setTimeout(function() {
+setTimeout(function() {
   console.log('this console.log statement should not make node crash');
 }, 1);
diff --git a/test/parallel/test-repl-autolibs.js b/test/parallel/test-repl-autolibs.js
index 05cc299f56..15f779d3b1 100644
--- a/test/parallel/test-repl-autolibs.js
+++ b/test/parallel/test-repl-autolibs.js
@@ -8,7 +8,7 @@ var repl = require('repl');
 common.globalCheck = false;
 
 const putIn = new common.ArrayStream();
-var testMe = repl.start('', putIn, null, true);
+repl.start('', putIn, null, true);
 
 test1();
 
diff --git a/test/parallel/test-repl-syntax-error-stack.js b/test/parallel/test-repl-syntax-error-stack.js
index 11e335e285..ebf0b2e4d8 100644
--- a/test/parallel/test-repl-syntax-error-stack.js
+++ b/test/parallel/test-repl-syntax-error-stack.js
@@ -16,7 +16,7 @@ common.ArrayStream.prototype.write = function(output) {
 };
 
 const putIn = new common.ArrayStream();
-const testMe = repl.start('', putIn);
+repl.start('', putIn);
 let file = path.resolve(__dirname, '../fixtures/syntax/bad_syntax');
 
 if (common.isWindows)
diff --git a/test/parallel/test-stream-pipe-error-handling.js b/test/parallel/test-stream-pipe-error-handling.js
index 8b674bffbd..88a70fb58e 100644
--- a/test/parallel/test-stream-pipe-error-handling.js
+++ b/test/parallel/test-stream-pipe-error-handling.js
@@ -38,7 +38,6 @@ var Stream = require('stream').Stream;
 })();
 
 (function testErrorWithRemovedListenerThrows() {
-  var EE = require('events').EventEmitter;
   var R = Stream.Readable;
   var W = Stream.Writable;
 
@@ -73,7 +72,6 @@ var Stream = require('stream').Stream;
 })();
 
 (function testErrorWithRemovedListenerThrows() {
-  var EE = require('events').EventEmitter;
   var R = Stream.Readable;
   var W = Stream.Writable;
 
diff --git a/test/parallel/test-stream-push-order.js b/test/parallel/test-stream-push-order.js
index 0bbcdf522b..f09cf95f37 100644
--- a/test/parallel/test-stream-push-order.js
+++ b/test/parallel/test-stream-push-order.js
@@ -21,7 +21,7 @@ s._read = function(n) {
   }
 };
 
-var v = s.read(0);
+s.read(0);
 
 // ACTUALLY [1, 3, 5, 6, 4, 2]
 
diff --git a/test/parallel/test-stream-unshift-read-race.js b/test/parallel/test-stream-unshift-read-race.js
index 253427e391..8239a380de 100644
--- a/test/parallel/test-stream-unshift-read-race.js
+++ b/test/parallel/test-stream-unshift-read-race.js
@@ -13,7 +13,6 @@ var stream = require('stream');
 var hwm = 10;
 var r = stream.Readable({ highWaterMark: hwm });
 var chunks = 10;
-var t = (chunks * 5);
 
 var data = new Buffer(chunks * hwm + Math.ceil(hwm / 2));
 for (var i = 0; i < data.length; i++) {
diff --git a/test/parallel/test-stream-writev.js b/test/parallel/test-stream-writev.js
index 88933508fb..5b07dd1119 100644
--- a/test/parallel/test-stream-writev.js
+++ b/test/parallel/test-stream-writev.js
@@ -30,11 +30,9 @@ function test(decode, uncork, multi, next) {
   function cnt(msg) {
     expectCount++;
     var expect = expectCount;
-    var called = false;
     return function(er) {
       if (er)
         throw er;
-      called = true;
       counter++;
       assert.equal(counter, expect);
     };
diff --git a/test/parallel/test-stream2-compatibility.js b/test/parallel/test-stream2-compatibility.js
index 76cb594229..2d62d63907 100644
--- a/test/parallel/test-stream2-compatibility.js
+++ b/test/parallel/test-stream2-compatibility.js
@@ -5,7 +5,6 @@ var W = require('_stream_writable');
 var assert = require('assert');
 
 var util = require('util');
-var EE = require('events').EventEmitter;
 
 var ondataCalled = 0;
 
diff --git a/test/parallel/test-stream2-large-read-stall.js b/test/parallel/test-stream2-large-read-stall.js
index 84457c7e3e..6a38baac5d 100644
--- a/test/parallel/test-stream2-large-read-stall.js
+++ b/test/parallel/test-stream2-large-read-stall.js
@@ -53,9 +53,6 @@ function push() {
     setTimeout(push);
 }
 
-// start the flow
-var ret = r.read(0);
-
 process.on('exit', function() {
   assert.equal(pushes, PUSHCOUNT + 1);
   assert(endEmitted);
diff --git a/test/parallel/test-stream2-objects.js b/test/parallel/test-stream2-objects.js
index e79b8f9524..e67359eff2 100644
--- a/test/parallel/test-stream2-objects.js
+++ b/test/parallel/test-stream2-objects.js
@@ -167,8 +167,6 @@ test('read(0) for object streams', function(t) {
   r.push('foobar');
   r.push(null);
 
-  var v = r.read(0);
-
   r.pipe(toArray(function(array) {
     assert.deepEqual(array, ['foobar']);
 
diff --git a/test/parallel/test-stream2-readable-from-list.js b/test/parallel/test-stream2-readable-from-list.js
index d4b42b60af..ab9d9c5d72 100644
--- a/test/parallel/test-stream2-readable-from-list.js
+++ b/test/parallel/test-stream2-readable-from-list.js
@@ -39,8 +39,6 @@ process.nextTick(run);
 
 
 test('buffers', function(t) {
-  // have a length
-  var len = 16;
   var list = [ new Buffer('foog'),
                new Buffer('bark'),
                new Buffer('bazy'),
@@ -69,8 +67,6 @@ test('buffers', function(t) {
 });
 
 test('strings', function(t) {
-  // have a length
-  var len = 16;
   var list = [ 'foog',
                'bark',
                'bazy',
diff --git a/test/parallel/test-stream2-transform.js b/test/parallel/test-stream2-transform.js
index 7dad573483..11ee45915c 100644
--- a/test/parallel/test-stream2-transform.js
+++ b/test/parallel/test-stream2-transform.js
@@ -303,13 +303,10 @@ test('passthrough event emission', function(t) {
   var pt = new PassThrough();
   var emits = 0;
   pt.on('readable', function() {
-    var state = pt._readableState;
     console.error('>>> emit readable %d', emits);
     emits++;
   });
 
-  var i = 0;
-
   pt.write(new Buffer('foog'));
 
   console.error('need emit 0');
diff --git a/test/parallel/test-timers-ordering.js b/test/parallel/test-timers-ordering.js
index 5da88967e3..cef91e58e7 100644
--- a/test/parallel/test-timers-ordering.js
+++ b/test/parallel/test-timers-ordering.js
@@ -3,13 +3,10 @@ require('../common');
 var assert = require('assert');
 var Timer = process.binding('timer_wrap').Timer;
 
-var i;
-
 var N = 30;
 
 var last_i = 0;
 var last_ts = 0;
-var start = Timer.now();
 
 var f = function(i) {
   if (i <= N) {
diff --git a/test/parallel/test-timers-zero-timeout.js b/test/parallel/test-timers-zero-timeout.js
index 78445ac659..ab0c38f608 100644
--- a/test/parallel/test-timers-zero-timeout.js
+++ b/test/parallel/test-timers-zero-timeout.js
@@ -7,7 +7,7 @@ var assert = require('assert');
   var ncalled = 0;
 
   setTimeout(f, 0, 'foo', 'bar', 'baz');
-  var timer = setTimeout(function() {}, 0);
+  setTimeout(function() {}, 0);
 
   function f(a, b, c) {
     assert.equal(a, 'foo');
diff --git a/test/parallel/test-url.js b/test/parallel/test-url.js
index a912b43d82..cd097be243 100644
--- a/test/parallel/test-url.js
+++ b/test/parallel/test-url.js
@@ -1514,9 +1514,6 @@ relativeTests2.forEach(function(relativeTest) {
 //if format and parse are inverse operations then
 //resolveObject(parse(x), y) == parse(resolve(x, y))
 
-//host and hostname are special, in this case a '' value is important
-var emptyIsImportant = {'host': true, 'hostname': ''};
-
 //format: [from, path, expected]
 relativeTests.forEach(function(relativeTest) {
   var actual = url.resolveObject(url.parse(relativeTest[0]), relativeTest[1]),