diff --git a/ChangeLog b/ChangeLog
index 7e6a971283..8029e9f63d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Wed Nov 27 04:46:55 2013  Aaron Patterson <aaron@tenderlovemaking.com>
+
+	* ext/psych/lib/psych/scalar_scanner.rb: fix regexp for matching TIME
+	  strings.
+	* test/psych/test_date_time.rb: test for change.
+	  Fixes: https://github.com/tenderlove/psych/issues/171
+
 Wed Nov 27 02:26:58 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* string.c (str_new4): copy the original capacity so that memsize of
diff --git a/ext/psych/lib/psych/scalar_scanner.rb b/ext/psych/lib/psych/scalar_scanner.rb
index 068fc0e3cf..5a805981b1 100644
--- a/ext/psych/lib/psych/scalar_scanner.rb
+++ b/ext/psych/lib/psych/scalar_scanner.rb
@@ -5,7 +5,7 @@ module Psych
   # Scan scalars for built in types
   class ScalarScanner
     # Taken from http://yaml.org/type/timestamp.html
-    TIME = /^\d{4}-\d{1,2}-\d{1,2}([Tt]|\s+)\d{1,2}:\d\d:\d\d(\.\d*)?(\s*Z|[-+]\d{1,2}(:\d\d)?)?/
+    TIME = /^\d{4}-\d{1,2}-\d{1,2}(?:[Tt]|\s+)\d{1,2}:\d\d:\d\d(?:\.\d*)?(?:\s*(?:Z|[-+]\d{1,2}:?(?:\d\d)?))?$/
 
     # Taken from http://yaml.org/type/float.html
     FLOAT = /^(?:[-+]?([0-9][0-9_,]*)?\.[0-9]*([eE][-+][0-9]+)?(?# base 10)
diff --git a/test/psych/test_date_time.rb b/test/psych/test_date_time.rb
index 9a8e37bc67..91de6a4841 100644
--- a/test/psych/test_date_time.rb
+++ b/test/psych/test_date_time.rb
@@ -3,6 +3,10 @@ require 'date'
 
 module Psych
   class TestDateTime < TestCase
+    def test_invalid_date
+      assert_cycle "2013-10-31T10:40:07-000000000000033"
+    end
+
     def test_string_tag
       dt = DateTime.now
       yaml = Psych.dump dt