diff --git a/reactos/include/psdk/basetsd.h b/reactos/include/psdk/basetsd.h
index 8563ed44669..a39f06a787b 100644
--- a/reactos/include/psdk/basetsd.h
+++ b/reactos/include/psdk/basetsd.h
@@ -23,7 +23,7 @@
 #error Not supported.
 #endif
 
-#if !defined(_X86_) && !defined(_AMD64) && !defined(_IA64_) && !defined(_ALPHA_) && \
+#if !defined(_X86_) && !defined(_AMD64_) && !defined(_IA64_) && !defined(_ALPHA_) && \
     !defined(_ARM_) && !defined(_PPC_) && !defined(_MIPS_) && !defined(_68K_)
 
 #if defined(_M_AMD64) || defined(__x86_64__)
diff --git a/reactos/include/psdk/windows.h b/reactos/include/psdk/windows.h
index a68d1b48655..569b693abf8 100644
--- a/reactos/include/psdk/windows.h
+++ b/reactos/include/psdk/windows.h
@@ -17,7 +17,7 @@
 #include <msvctarget.h>
 #endif
 
-#if !defined(_X86_) && !defined(_AMD64) && !defined(_IA64_) && !defined(_ALPHA_) && \
+#if !defined(_X86_) && !defined(_AMD64_) && !defined(_IA64_) && !defined(_ALPHA_) && \
     !defined(_ARM_) && !defined(_PPC_) && !defined(_MIPS_) && !defined(_68K_)
 
 #if defined(_M_AMD64) || defined(__x86_64__)