diff --git a/lib/child_process.js b/lib/child_process.js
index cef093a0b74..b3e6383c752 100644
--- a/lib/child_process.js
+++ b/lib/child_process.js
@@ -153,6 +153,12 @@ exports.fork = function(modulePath, args, options) {
   args = args ? args.slice(0) : [];
   args.unshift(modulePath);
 
+  if (options.thread) {
+    if (!process.features.isolates) {
+      throw new Error('node compiled without isolate support');
+    }
+  }
+
   if (options.stdinStream) {
     throw new Error('stdinStream not allowed for fork()');
   }
diff --git a/test/simple/test-child-process-fork.js b/test/simple/test-child-process-fork.js
index 41cc28c72e4..ea99ae7704b 100644
--- a/test/simple/test-child-process-fork.js
+++ b/test/simple/test-child-process-fork.js
@@ -24,7 +24,13 @@ var common = require('../common');
 var fork = require('child_process').fork;
 var args = ['foo', 'bar'];
 
-var n = fork(common.fixturesDir + '/child-process-spawn-node.js', args);
+var options = {
+  thread: process.TEST_ISOLATE ? true : false
+};
+
+var n = fork(common.fixturesDir + '/child-process-spawn-node.js',
+             args,
+             options);
 assert.deepEqual(args, ['foo', 'bar']);
 
 var messageCount = 0;
diff --git a/test/simple/test-isolates2.js b/test/simple/test-isolates2.js
new file mode 100644
index 00000000000..1823b8fe76c
--- /dev/null
+++ b/test/simple/test-isolates2.js
@@ -0,0 +1,13 @@
+// Skip this test if Node is not compiled with isolates support.
+if (!process.features.isolates) return;
+
+var assert = require('assert');
+
+// This is the same test as test-child-process-fork except it uses isolates
+// instead of processes. process.TEST_ISOLATE is a ghetto method of passing
+// some information into the other test.
+process.TEST_ISOLATE = true;
+require('./test-child-process-fork');
+
+var numThreads = process.binding('isolates').count();
+assert.ok(numThreads > 1);