diff --git a/winsup/w32api/ChangeLog b/winsup/w32api/ChangeLog
index 5dd07d906..dfff5750e 100644
--- a/winsup/w32api/ChangeLog
+++ b/winsup/w32api/ChangeLog
@@ -1,3 +1,11 @@
+2003-02-05  Earnie Boyd  <earnie@users.sf.net>
+
+	* include/basetypes.h (_GUID_DEFINED): Add deprecation warning, start
+	using GUID_DEFINED instead.
+	* include/sqltypes.h: Ditto.
+	* include/winnt.h: Ditto.
+	* include/ddk/scsiwmi.h: Ditto.
+
 2003-02-04  Danny Smith  <dannysmith@users.sourceforge.net>
 
 	* include/shlwapi.h (PathRelativePathTo[AW]): Correct
diff --git a/winsup/w32api/include/basetyps.h b/winsup/w32api/include/basetyps.h
index e1e36501b..a5daba4e5 100644
--- a/winsup/w32api/include/basetyps.h
+++ b/winsup/w32api/include/basetyps.h
@@ -81,8 +81,12 @@ DECLARE_INTERFACE_(I,IUnknown) \
 
 #endif /* __OBJC__ */
 
-#ifndef _GUID_DEFINED /* also defined in winnt.h */
-#define _GUID_DEFINED
+#ifdef _GUID_DEFINED
+# warning _GUID_DEFINED is deprecated, use GUID_DEFINED instead
+#endif
+
+#if ! (defined _GUID_DEFINED || defined GUID_DEFINED) /* also defined in winnt.h */
+#define GUID_DEFINED
 typedef struct _GUID
 {
     unsigned long Data1;
@@ -90,7 +94,7 @@ typedef struct _GUID
     unsigned short Data3;
     unsigned char Data4[8];
 } GUID,*REFGUID,*LPGUID;
-#endif /* _GUID_DEFINED */
+#endif /* GUID_DEFINED */
 #ifndef UUID_DEFINED
 #define UUID_DEFINED
 typedef GUID UUID;
diff --git a/winsup/w32api/include/ddk/scsiwmi.h b/winsup/w32api/include/ddk/scsiwmi.h
index 9f3aebc55..684271593 100644
--- a/winsup/w32api/include/ddk/scsiwmi.h
+++ b/winsup/w32api/include/ddk/scsiwmi.h
@@ -46,8 +46,12 @@ typedef struct _SCSIWMI_REQUEST_CONTEXT {
   ULONG  ReturnSize;
 } SCSIWMI_REQUEST_CONTEXT, *PSCSIWMI_REQUEST_CONTEXT;
 
-#ifndef _GUID_DEFINED
-#define _GUID_DEFINED
+#ifdef _GUID_DEFINED
+# warning _GUID_DEFINED is deprecated, use GUID_DEFINED instead
+#endif
+
+#if ! (defined _GUID_DEFINED || defined GUID_DEFINED)
+#define GUID_DEFINED
 typedef struct _GUID {
     unsigned long  Data1;
     unsigned short Data2;
diff --git a/winsup/w32api/include/sqltypes.h b/winsup/w32api/include/sqltypes.h
index b83188494..fcc713550 100644
--- a/winsup/w32api/include/sqltypes.h
+++ b/winsup/w32api/include/sqltypes.h
@@ -142,7 +142,12 @@ typedef struct tagSQL_NUMERIC_STRUCT {
 } SQL_NUMERIC_STRUCT;
 #endif  /* ODBCVER >= 0x0300 */
 #if (ODBCVER >= 0x0350)
+
 #ifdef _GUID_DEFINED
+# warning _GUID_DEFINED is deprecated, use GUID_DEFINED instead
+#endif
+
+#if defined _GUID_DEFINED || defined GUID_DEFINED
 typedef GUID SQLGUID;
 #else
 typedef struct tagSQLGUID{
@@ -151,7 +156,7 @@ typedef struct tagSQLGUID{
     WORD Data3;
     BYTE Data4[ 8 ];
 } SQLGUID;
-#endif  /* _GUID_DEFINED */
+#endif  /* GUID_DEFINED */
 #endif  /* ODBCVER >= 0x0350 */
 #endif     /* RC_INVOKED */
 #ifdef __cplusplus
diff --git a/winsup/w32api/include/winnt.h b/winsup/w32api/include/winnt.h
index 43fb038ba..88766ac0d 100644
--- a/winsup/w32api/include/winnt.h
+++ b/winsup/w32api/include/winnt.h
@@ -1152,8 +1152,13 @@ typedef DWORD FLONG;
 #define IO_REPARSE_TAG_MOUNT_POINT 0xA0000003
 #ifndef RC_INVOKED
 typedef DWORD ACCESS_MASK, *PACCESS_MASK;
-#ifndef _GUID_DEFINED /* also defined in basetyps.h */
-#define _GUID_DEFINED
+
+#ifdef _GUID_DEFINED
+# warning _GUID_DEFINED is deprecated, use GUID_DEFINED instead
+#endif
+
+#if ! (defined _GUID_DEFINED || defined GUID_DEFINED) /* also defined in basetyps.h */
+#define GUID_DEFINED
 typedef struct _GUID {
 	unsigned long  Data1;
 	unsigned short Data2;
@@ -1161,7 +1166,7 @@ typedef struct _GUID {
 	unsigned char  Data4[8];
 } GUID, *REFGUID, *LPGUID;
 #define SYSTEM_LUID { QuadPart:999 }
-#endif /* _GUID_DEFINED */
+#endif /* GUID_DEFINED */
 typedef struct _GENERIC_MAPPING {
 	ACCESS_MASK GenericRead;
 	ACCESS_MASK GenericWrite;