diff --git a/IPython/core/interactiveshell.py b/IPython/core/interactiveshell.py
index 7d7d0fe..b78654e 100644
--- a/IPython/core/interactiveshell.py
+++ b/IPython/core/interactiveshell.py
@@ -911,7 +911,8 @@ class InteractiveShell(SingletonConfigurable):
         try:
             main_mod = self._main_mod_cache[filename]
         except KeyError:
-            main_mod = self._main_mod_cache[filename] = types.ModuleType(modname,
+            main_mod = self._main_mod_cache[filename] = types.ModuleType(
+                        py3compat.cast_bytes_py2(modname),
                         doc="Module created for script run in IPython")
         else:
             main_mod.__dict__.clear()
diff --git a/IPython/core/tests/test_interactiveshell.py b/IPython/core/tests/test_interactiveshell.py
index 56211a8..de8d8d7 100644
--- a/IPython/core/tests/test_interactiveshell.py
+++ b/IPython/core/tests/test_interactiveshell.py
@@ -472,6 +472,12 @@ class InteractiveShellTestCase(unittest.TestCase):
         with open(filename, 'r') as f:
             self.assertEqual(f.read(), 'blah')
 
+    def test_new_main_mod(self):
+        # Smoketest to check that this accepts a unicode module name
+        name = u'jiefmw'
+        mod = ip.new_main_mod(u'%s.py' % name, name)
+        self.assertEqual(mod.__name__, name)
+
 class TestSafeExecfileNonAsciiPath(unittest.TestCase):
 
     @onlyif_unicode_paths