diff --git a/lib/dm-serializer/to_json.rb b/lib/dm-serializer/to_json.rb
index 38c2e2b..d7aa57c 100644
--- a/lib/dm-serializer/to_json.rb
+++ b/lib/dm-serializer/to_json.rb
@@ -21,7 +21,13 @@ def as_json(options = {})
 
       properties_to_serialize(options).each do |property|
         property_name = property.name
-        result[property_name] = __send__(property_name)
+        value = __send__(property_name)
+        result[property_name] = case property
+                                when DataMapper::Property::Discriminator
+                                  value.to_s
+                                else
+                                  value
+                                end
       end
 
       # add methods
diff --git a/spec/fixtures/vehicle.rb b/spec/fixtures/vehicle.rb
new file mode 100644
index 0000000..af7f8cd
--- /dev/null
+++ b/spec/fixtures/vehicle.rb
@@ -0,0 +1,14 @@
+class Vehicle
+  include DataMapper::Resource
+  property :id, Serial
+  property :name, String
+  property :type, Discriminator
+end
+
+class Car < Vehicle
+
+end
+
+class Motorcycle < Vehicle
+
+end
diff --git a/spec/public/to_json_spec.rb b/spec/public/to_json_spec.rb
index a349279..76ca6bf 100644
--- a/spec/public/to_json_spec.rb
+++ b/spec/public/to_json_spec.rb
@@ -68,4 +68,8 @@ def deserialize(result)
   it "handles nil for options" do
     expect { Cow.new.as_json(nil) }.to_not raise_error
   end
+
+  it "serializes Discriminator types as strings" do
+    Motorcycle.new.as_json[:type].should == "Motorcycle" 
+  end
 end