diff --git a/ChangeLog b/ChangeLog
index 17a0dd6076..6db823fe5c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Thu Jan  6 11:27:01 2011  Aaron Patterson <aaron@tenderlovemaking.com>
+
+	* ext/psych/lib/psych/json/tree_builder.rb (start_mapping): tags
+	  should not be included in JSON mapping
+
 Thu Jan  6 09:23:33 2011  Aaron Patterson <aaron@tenderlovemaking.com>
 
 	* lib/net/protocol.rb (eof?): BufferedIO should proxy eof? to the
diff --git a/ext/psych/lib/psych/json/tree_builder.rb b/ext/psych/lib/psych/json/tree_builder.rb
index 720ede7e1e..26fcb118d0 100644
--- a/ext/psych/lib/psych/json/tree_builder.rb
+++ b/ext/psych/lib/psych/json/tree_builder.rb
@@ -13,7 +13,7 @@ module Psych
       end
 
       def start_mapping anchor, tag, implicit, style
-        super(anchor, tag, implicit, Nodes::Mapping::FLOW)
+        super(anchor, nil, implicit, Nodes::Mapping::FLOW)
       end
 
       def start_sequence anchor, tag, implicit, style
diff --git a/test/psych/test_coder.rb b/test/psych/test_coder.rb
index 0fa01ca3b6..c171c5ad0d 100644
--- a/test/psych/test_coder.rb
+++ b/test/psych/test_coder.rb
@@ -89,6 +89,10 @@ module Psych
       end
     end
 
+    def test_json_dump_exclude_tag
+      refute_match('TestCoder::InitApi', Psych.to_json(InitApi.new))
+    end
+
     def test_map_takes_block
       coder = Psych::Coder.new 'foo'
       tag = coder.tag