diff --git a/lib/rbvmomi/connection.rb b/lib/rbvmomi/connection.rb
index f4313db2..378a3e65 100644
--- a/lib/rbvmomi/connection.rb
+++ b/lib/rbvmomi/connection.rb
@@ -132,10 +132,10 @@ def obj2xml xml, name, type, is_array, o, attrs={}
         end
       end
     when BasicTypes::ManagedObject
-      fail "expected #{expected.wsdl_name}, got #{o.class.wsdl_name} for field #{name.inspect}" if expected and not expected >= o.class
+      fail "expected #{expected.wsdl_name}, got #{o.class.wsdl_name} for field #{name.inspect}" if expected and not expected >= o.class and not expected == BasicTypes::AnyType
       xml.tag! name, o._ref, :type => o.class.wsdl_name
     when BasicTypes::DataObject
-      fail "expected #{expected.wsdl_name}, got #{o.class.wsdl_name} for field #{name.inspect}" if expected and not expected >= o.class
+      fail "expected #{expected.wsdl_name}, got #{o.class.wsdl_name} for field #{name.inspect}" if expected and not expected >= o.class and not expected == BasicTypes::AnyType
       xml.tag! name, attrs.merge("xsi:type" => o.class.wsdl_name) do
         o.class.full_props_desc.each do |desc|
           if o.props.member? desc['name'].to_sym
diff --git a/test/test_serialization.rb b/test/test_serialization.rb
index cd2f3540..c036e4ec 100644
--- a/test/test_serialization.rb
+++ b/test/test_serialization.rb
@@ -292,4 +292,20 @@ def test_time
 <root>2011-11-16T13:36:08-08:00</root>
     EOS
   end
+
+  # TODO test all types
+  def test_any_type
+    obj = 1
+    check <<-EOS, obj, 'xsd:anyType', false
+<root xsi:type="xsd:long">1</root>
+    EOS
+
+    obj = VIM::HostAccountSpec(:id => 'root', :password => 'foo')
+    check <<-EOS, obj, 'xsd:anyType', false
+<root xsi:type="HostAccountSpec">
+  <id>root</id>
+  <password>foo</password>
+</root>
+    EOS
+  end
 end