diff --git a/lib/doctest.js b/lib/doctest.js
index 339b2544..8a396d81 100644
--- a/lib/doctest.js
+++ b/lib/doctest.js
@@ -172,6 +172,7 @@
       case 'commonjs':
         return iifeWrap(unlines([
           'var __doctest = {',
+          '  require: require,',
           '  queue: [],',
           '  enqueue: function(io) { this.queue.push(io); }',
           '};',
diff --git a/test/index.js b/test/index.js
index 8a01e8f8..724def7e 100644
--- a/test/index.js
+++ b/test/index.js
@@ -249,6 +249,7 @@ testCommand(
   stdout: unlines([
     'void function() {',
     '  var __doctest = {',
+    '    require: require,',
     '    queue: [],',
     '    enqueue: function(io) { this.queue.push(io); }',
     '  };',