diff --git a/thrift.vim b/thrift.vim
index 4cadaf7..115e936 100644
--- a/thrift.vim
+++ b/thrift.vim
@@ -31,7 +31,7 @@
 
 " Keywords
 syn keyword thriftKeyword namespace cocoa_prefix
-syn keyword thriftKeyword csharp_namespace smalltalk_category smalltalk_prefix
+syn keyword thriftKeyword csharp_namespace
 syn keyword thriftKeyword php_namespace ruby_namespace py_module perl_package
 syn keyword thriftKeyword xsd_all xsd_optional xsd_nillable xsd_namespace xsd_attrs
 syn keyword thriftKeyword include cpp_include cpp_type const optional required