diff --git a/lib/rexml/parsers/baseparser.rb b/lib/rexml/parsers/baseparser.rb
index f66b968f..8d62391c 100644
--- a/lib/rexml/parsers/baseparser.rb
+++ b/lib/rexml/parsers/baseparser.rb
@@ -656,7 +656,7 @@ def parse_attributes(prefixes, curr_ns)
               prefixes << prefix unless prefix == "xml"
             end
 
-            if attributes.has_key?(name)
+            if attributes[name]
               msg = "Duplicate attribute #{name.inspect}"
               raise REXML::ParseException.new(msg, @source, self)
             end