diff --git a/lib/fs.js b/lib/fs.js
index 9645b7679a..eca2c8a615 100644
--- a/lib/fs.js
+++ b/lib/fs.js
@@ -514,15 +514,27 @@ if (isWindows) {
   // windows version
   fs.realpathSync = function realpathSync(p) {
     var p = path.resolve(p);
+    if (cache && Object.prototype.hasOwnProperty.call(cache, p)) {
+      return cache[p];
+    }
     fs.statSync(p);
+    if (cache) cache[p] = p;
     return p;
   };
 
   // windows version
-  fs.realpath = function(p, cb) {
+  fs.realpath = function(p, cache, cb) {
+    if (typeof cb !== 'function') {
+      cb = cache;
+      cache = null;
+    }
     var p = path.resolve(p);
+    if (cache && Object.prototype.hasOwnProperty.call(cache, p)) {
+      return cb(null, cache[p]);
+    }
     fs.stat(p, function(err) {
       if (err) cb(err);
+      if (cache) cache[p] = p;
       cb(null, p);
     });
   };
@@ -535,11 +547,16 @@ if (isWindows) {
   var nextPartRe = /(.*?)(?:[\/]+|$)/g;
 
   // posix version
-  fs.realpathSync = function realpathSync(p) {
+  fs.realpathSync = function realpathSync(p, cache) {
     // make p is absolute
     p = path.resolve(p);
 
-    var seenLinks = {},
+    if (cache && Object.prototype.hasOwnProperty.call(cache, p)) {
+      return cache[p];
+    }
+
+    var original = p,
+        seenLinks = {},
         knownHard = {};
 
     // current character position in p
@@ -564,38 +581,61 @@ if (isWindows) {
       pos = nextPartRe.lastIndex;
 
       // continue if not a symlink, or if root
-      if (!base || knownHard[base]) {
-        continue;
-      }
-      var stat = fs.lstatSync(base);
-      if (!stat.isSymbolicLink()) {
-        knownHard[base] = true;
+      if (!base || knownHard[base] || (cache && cache[base] === base)) {
         continue;
       }
 
-      // read the link if it wasn't read before
-      var id = stat.dev.toString(32) + ':' + stat.ino.toString(32);
-      if (!seenLinks[id]) {
-        fs.statSync(base);
-        seenLinks[id] = fs.readlinkSync(base);
+      var resolvedLink;
+      if (cache && Object.prototype.hasOwnProperty.call(cache, base)) {
+        // some known symbolic link.  no need to stat again.
+        resolvedLink = cache[base];
+      } else {
+        var stat = fs.lstatSync(base);
+        if (!stat.isSymbolicLink()) {
+          knownHard[base] = true;
+          if (cache) cache[base] = base;
+          continue;
+        }
+
+        // read the link if it wasn't read before
+        var id = stat.dev.toString(32) + ':' + stat.ino.toString(32);
+        if (!seenLinks[id]) {
+          fs.statSync(base);
+          seenLinks[id] = fs.readlinkSync(base);
+          resolvedLink = path.resolve(previous, seenLinks[id]);
+          // track this, if given a cache.
+          if (cache) cache[base] = resolvedLink;
+        }
       }
 
       // resolve the link, then start over
-      p = path.resolve(previous, seenLinks[id], p.slice(pos));
+      p = path.resolve(resolvedLink, p.slice(pos));
       pos = 0;
       previous = base = current = '';
     }
 
+    if (cache) cache[original] = p;
+
     return p;
   };
 
 
   // posix version
-  fs.realpath = function realpath(p, cb) {
+  fs.realpath = function realpath(p, cache, cb) {
+    if (typeof cb !== 'function') {
+      cb = cache;
+      cache = null;
+    }
+
     // make p is absolute
     p = path.resolve(p);
 
-    var seenLinks = {},
+    if (cache && Object.prototype.hasOwnProperty.call(cache, p)) {
+      return cb(null, cache[p]);
+    }
+
+    var original = p,
+        seenLinks = {},
         knownHard = {};
 
     // current character position in p
@@ -613,6 +653,7 @@ if (isWindows) {
     function LOOP() {
       // stop if scanned past end of path
       if (pos >= p.length) {
+        if (cache) cache[original] = p;
         return cb(null, p);
       }
 
@@ -624,11 +665,16 @@ if (isWindows) {
       base = previous + result[1];
       pos = nextPartRe.lastIndex;
 
-      // continue if known to be hard or if root
-      if (!base || knownHard[base]) {
+      // continue if known to be hard or if root or in cache already.
+      if (!base || knownHard[base] || (cache && cache[base] === base)) {
         return process.nextTick(LOOP);
       }
 
+      if (cache && Object.prototype.hasOwnProperty.call(cache, base)) {
+        // known symbolic link.  no need to stat again.
+        return gotResolvedLink(cache[base]);
+      }
+
       return fs.lstat(base, gotStat);
     }
 
@@ -638,6 +684,7 @@ if (isWindows) {
       // if not a symlink, skip to the next path part
       if (!stat.isSymbolicLink()) {
         knownHard[base] = true;
+        if (cache) cache[base] = base;
         return process.nextTick(LOOP);
       }
 
@@ -645,7 +692,7 @@ if (isWindows) {
       // call gotTarget as soon as the link target is known
       var id = stat.dev.toString(32) + ':' + stat.ino.toString(32);
       if (seenLinks[id]) {
-        return gotTarget(null, seenLinks[id]);
+        return gotTarget(null, seenLinks[id], base);
       }
       fs.stat(base, function(err) {
         if (err) return cb(err);
@@ -656,11 +703,18 @@ if (isWindows) {
       });
     }
 
-    function gotTarget(err, target) {
+    function gotTarget(err, target, base) {
       if (err) return cb(err);
 
+      var resolvedLink = path.resolve(previous, target);
+      if (cache) cache[base] = resolvedLink;
+      gotResolvedLink(resolvedLink);
+    }
+
+    function gotResolvedLink(resolvedLink) {
+
       // resolve the link, then start over
-      p = path.resolve(previous, target, p.slice(pos));
+      p = path.resolve(resolvedLink, p.slice(pos));
       pos = 0;
       previous = base = current = '';
 
diff --git a/lib/module.js b/lib/module.js
index 99e839ee36..b5724ffaf6 100644
--- a/lib/module.js
+++ b/lib/module.js
@@ -88,12 +88,17 @@ function tryPackage(requestPath, exts) {
   return tryFile(filename) || tryExtensions(filename, exts);
 }
 
+// In order to minimize unnecessary lstat() calls,
+// this cache is a list of known-real paths.
+// Set to an empty object to reset.
+Module._realpathCache = {}
+
 // check if the file exists and is not a directory
 function tryFile(requestPath) {
   var fs = NativeModule.require('fs');
   var stats = statPath(requestPath);
   if (stats && !stats.isDirectory()) {
-    return fs.realpathSync(requestPath);
+    return fs.realpathSync(requestPath, Module._realpathCache);
   }
   return false;
 }
diff --git a/test/simple/test-fs-realpath.js b/test/simple/test-fs-realpath.js
index fec0bc321e..5d412785db 100644
--- a/test/simple/test-fs-realpath.js
+++ b/test/simple/test-fs-realpath.js
@@ -363,6 +363,31 @@ function test_abs_with_kids(cb) {
   });
 }
 
+function test_lying_cache_liar(cb) {
+  // this should not require *any* stat calls, since everything
+  // checked by realpath will be found in the cache.
+  console.log('test_lying_cache_liar');
+  var cache = { '/foo/bar/baz/bluff' : '/foo/bar/bluff',
+                '/1/2/3/4/5/6/7' : '/1',
+                '/a' : '/a',
+                '/a/b' : '/a/b',
+                '/a/b/c' : '/a/b',
+                '/a/b/d' : '/a/b/d' };
+  var rps = fs.realpathSync('/foo/bar/baz/bluff', cache);
+  assert.equal(cache['/foo/bar/baz/bluff'], rps);
+  fs.realpath('/1/2/3/4/5/6/7', cache, function(er, rp) {
+    assert.equal(cache['/1/2/3/4/5/6/7'], rp);
+  });
+
+  var test = '/a/b/c/d',
+      expect = '/a/b/d';
+  var actual = fs.realpathSync(test, cache);
+  assert.equal(expect, actual);
+  fs.realpath(test, cache, function(er, actual) {
+    assert.equal(expect, actual);
+  });
+}
+
 // ----------------------------------------------------------------------------
 
 var tests = [
@@ -376,7 +401,8 @@ var tests = [
   test_deep_symlink_mix,
   test_non_symlinks,
   test_escape_cwd,
-  test_abs_with_kids
+  test_abs_with_kids,
+  test_lying_cache_liar
 ];
 var numtests = tests.length;
 function runNextTest(err) {