diff --git a/include/ddraw.h b/include/ddraw.h
index 159c4f6..5a63d7a 100644
--- a/include/ddraw.h
+++ b/include/ddraw.h
@@ -32,6 +32,7 @@
 /*****************************************************************************
  * Predeclare the interfaces
  */
+#ifndef __DDRAW_GUID_DEFINED__
 DEFINE_GUID( CLSID_DirectDraw,		0xD7B70EE0,0x4340,0x11CF,0xB0,0x63,0x00,0x20,0xAF,0xC2,0xCD,0x35 );
 DEFINE_GUID( CLSID_DirectDraw7,         0x3C305196,0x50DB,0x11D3,0x9C,0xFE,0x00,0xC0,0x4F,0xD9,0x30,0xC5 );
 DEFINE_GUID( CLSID_DirectDrawClipper,	0x593817A0,0x7DB3,0x11CF,0xA2,0xDE,0x00,0xAA,0x00,0xb9,0x33,0x56 );
@@ -48,6 +49,7 @@
 DEFINE_GUID( IID_IDirectDrawClipper,	0x6C14DB85,0xA733,0x11CE,0xA5,0x21,0x00,0x20,0xAF,0x0B,0xE5,0x60 );
 DEFINE_GUID( IID_IDirectDrawColorControl,0x4B9F0EE0,0x0D7E,0x11D0,0x9B,0x06,0x00,0xA0,0xC9,0x03,0xA3,0xB8 );
 DEFINE_GUID( IID_IDirectDrawGammaControl,0x69C11C3E,0xB46B,0x11D1,0xAD,0x7A,0x00,0xC0,0x4F,0xC2,0x9B,0x4E );
+#endif
 
 typedef struct IDirectDraw IDirectDraw,*LPDIRECTDRAW;
 typedef struct IDirectDraw2 IDirectDraw2,*LPDIRECTDRAW2;