diff --git a/ChangeLog b/ChangeLog
index eb8ef2d64f..421178595c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+Tue Oct 23 06:04:07 2012  Aaron Patterson <aaron@tenderlovemaking.com>
+
+	* ext/psych/lib/psych/scalar_scanner.rb: Fix scalar_scanner to
+	  understand strings starting with an underscore and containing only
+	  digits.  Thanks Kelley Reynolds.
+
+	* test/psych/test_scalar_scanner.rb: test for fix
+
 Tue Oct 23 06:00:41 2012  Aaron Patterson <aaron@tenderlovemaking.com>
 
 	* ext/psych/lib/psych.rb: Changed comment in psych.rb to update new
diff --git a/ext/psych/lib/psych/scalar_scanner.rb b/ext/psych/lib/psych/scalar_scanner.rb
index fa2d385a63..8727adecb4 100644
--- a/ext/psych/lib/psych/scalar_scanner.rb
+++ b/ext/psych/lib/psych/scalar_scanner.rb
@@ -24,7 +24,7 @@ module Psych
       return string if @string_cache.key?(string)
 
       case string
-      when /^[A-Za-z~]/
+      when /^[A-Za-z_~]/
         if string.length > 5
           @string_cache[string] = true
           return string
diff --git a/test/psych/test_scalar_scanner.rb b/test/psych/test_scalar_scanner.rb
index cf0dfff6aa..1397020c88 100644
--- a/test/psych/test_scalar_scanner.rb
+++ b/test/psych/test_scalar_scanner.rb
@@ -87,5 +87,9 @@ module Psych
     def test_scan_true
       assert_equal true, ss.tokenize('true')
     end
+
+    def test_scan_strings_starting_with_underscores
+      assert_equal "_100", ss.tokenize('_100')
+    end
   end
 end