diff --git a/lib/rb/lib/thrift/union.rb b/lib/rb/lib/thrift/union.rb
index 0b41ed4..e443d42 100644
--- a/lib/rb/lib/thrift/union.rb
+++ b/lib/rb/lib/thrift/union.rb
@@ -21,6 +21,14 @@
   class Union
     def initialize(name=nil, value=nil)
       if name
+        if name.is_a? Hash
+          if name.size > 1
+            raise "#{self.class} cannot be instantiated with more than one field!"
+          end
+
+          name, value = name.keys.first, name.values.first
+        end
+
         if value.nil?
           raise Exception, "Union #{self.class} cannot be instantiated with setfield and nil value!"
         end
diff --git a/lib/rb/spec/union_spec.rb b/lib/rb/spec/union_spec.rb
index 4835288..07a3f94 100644
--- a/lib/rb/spec/union_spec.rb
+++ b/lib/rb/spec/union_spec.rb
@@ -141,5 +141,11 @@
       swu2.read(proto)
       swu2.should == swu
     end
+    
+    it "should support old style constructor" do
+      union = My_union.new(:integer32 => 26)
+      union.get_set_field.should == :integer32
+      union.get_value.should == 26
+    end
   end
 end