diff --git a/include/git2/common.h b/include/git2/common.h
index 170ef340db9..a66f9c3804a 100644
--- a/include/git2/common.h
+++ b/include/git2/common.h
@@ -51,7 +51,7 @@
 # define GIT_FORMAT_PRINTF(a,b) /* empty */
 #endif
 
-#if (defined(_WIN32) || defined(_WIN64)) && !defined(__CYGWIN__)
+#if (defined(_WIN32)) && !defined(__CYGWIN__)
 #define GIT_WIN32 1
 #endif
 
diff --git a/src/xdiff/xinclude.h b/src/xdiff/xinclude.h
index 7d7b77b3ea4..4a1cde9092b 100644
--- a/src/xdiff/xinclude.h
+++ b/src/xdiff/xinclude.h
@@ -29,7 +29,7 @@
 #include <string.h>
 #include <limits.h>
 
-#ifdef GIT_WIN32
+#ifdef _WIN32
 #else
 #include <unistd.h>
 #endif