diff --git a/include/comcat.h b/include/comcat.h
index 05e13741146..2d8563d114c 100644
--- a/include/comcat.h
+++ b/include/comcat.h
@@ -4,6 +4,13 @@
 #include "rpc.h"
 #include "rpcndr.h"
 
+#ifndef COM_NO_WINDOWS_H
+#include "windows.h"
+#include "ole2.h"
+#endif
+
+#include "unknwn.h"
+
 typedef GUID CATID;
 typedef REFGUID REFCATID;
 
diff --git a/include/rpc.h b/include/rpc.h
index feef48346f4..06e5c0f634b 100644
--- a/include/rpc.h
+++ b/include/rpc.h
@@ -33,5 +33,9 @@ typedef GUID UUID;
 RPC_STATUS RPC_ENTRY UuidCreate(UUID *Uuid);
 
 #include "rpcdce.h"
+/* #include "rpcnsi.h" */
+/* #include "rpcnterr.h" */
+/* #include "excpt.h" */
+#include "winerror.h"
 
 #endif /*__WINE_RPC_H */