diff --git a/lib/sys.js b/lib/sys.js
index b255cd6cec..ee2f2fd263 100644
--- a/lib/sys.js
+++ b/lib/sys.js
@@ -98,7 +98,21 @@ var formatter = function(value, indent, parents) {
         });
       } else {
         return formatObject(value, indent, parents, '{}', function(x, f) {
-          return f(x) + ': ' + f(value[x]);
+          var child;
+          if (value.__lookupGetter__(x)) {
+            if (value.__lookupSetter__(x)) {
+              child = "[Dynamic Property]";
+            } else {
+              child = "[Dynamic Property Read-only]";
+            }
+          } else {
+            if (value.__lookupSetter__(x)) {
+              child = "[Dynamic Property Write-only]";
+            } else {
+              child = f(value[x]);
+            }
+          }
+          return f(x) + ': ' + child;
         });
       }
       return buffer;
@@ -113,6 +127,7 @@ var formatter = function(value, indent, parents) {
 var formatObject = function(obj, indent, parents, parenthesis, entryFormatter) {
   var buffer = parenthesis[0];
   var values = [];
+  var x;
 
   var localFormatter = function(value) {
     return formatter(value, indent + ' ', parents);
diff --git a/test/mjsunit/test-sys.js b/test/mjsunit/test-sys.js
index 893efd0e3b..e8da2b3168 100644
--- a/test/mjsunit/test-sys.js
+++ b/test/mjsunit/test-sys.js
@@ -24,9 +24,23 @@ assert.equal('{\n "a": 1,\n "b": 2\n}', inspect({a: 1, b: 2}));
 assert.equal('{\n "a": {}\n}', inspect({'a': {}}));
 assert.equal('{\n "a": {\n  "b": 2\n }\n}', inspect({'a': {'b': 2}}));
 
+// Dynamic properties
+assert.equal(
+  "{\n \"readonly\": [Dynamic Property Read-only],\n \"readwrite\": [Dynamic Property],\n \"writeonly\": [Dynamic Property Write-only]\n}",
+  inspect({get readonly() {return 1;},get readwrite(){return 2;},set readwrite(value){},set writeonly(val){}})
+);
+
 var value = {};
 value['a'] = value;
 assert.equal('{\n "a": [Circular]\n}', inspect(value));
 value = Object.create([]);
 value.push(1);
-assert.equal('{\n "0": 1,\n "length": 1\n}', inspect(value));
\ No newline at end of file
+assert.equal('{\n "0": 1,\n "length": 1\n}', inspect(value));
+
+// Array with dynamic properties
+value = [1,2,3];
+value.__defineGetter__('growingLength', function () { this.push(true); return this.length; });
+assert.equal(
+  "{\n \"0\": 1,\n \"1\": 2,\n \"2\": 3,\n \"growingLength\": [Dynamic Property Read-only]\n}",
+  inspect(value)
+);
\ No newline at end of file