diff --git a/python/ray/function_manager.py b/python/ray/function_manager.py
index df01088aa..e72fe64f1 100644
--- a/python/ray/function_manager.py
+++ b/python/ray/function_manager.py
@@ -123,7 +123,9 @@ class FunctionDescriptor(object):
         try:
             # If we are running a script or are in IPython, include the source
             # code in the hash.
-            source = inspect.getsource(function).encode("ascii")
+            source = inspect.getsource(function)
+            if sys.version_info[0] >= 3:
+                source = source.encode()
             function_source_hasher.update(source)
             function_source_hash = function_source_hasher.digest()
         except (IOError, OSError, TypeError):
diff --git a/test/runtest.py b/test/runtest.py
index de0fe5699..7036e57f6 100644
--- a/test/runtest.py
+++ b/test/runtest.py
@@ -1,3 +1,4 @@
+# coding: utf-8
 from __future__ import absolute_import
 from __future__ import division
 from __future__ import print_function
@@ -2767,3 +2768,12 @@ def test_raylet_is_robust_to_random_messages(shutdown_only):
         return 1
 
     assert ray.get(f.remote()) == 1
+
+
+def test_non_ascii_comment(ray_start):
+    @ray.remote
+    def f():
+        # 日本語 Japanese comment
+        return 1
+
+    assert ray.get(f.remote()) == 1