diff --git a/sample/dns-example.c b/sample/dns-example.c
index c4fb64a5..15e48ce4 100644
--- a/sample/dns-example.c
+++ b/sample/dns-example.c
@@ -171,7 +171,7 @@ main(int c, char **v) {
 		++idx;
 	}
 
-#ifdef WIN32
+#ifdef _WIN32
 	{
 		WSADATA WSAData;
 		WSAStartup(0x101, &WSAData);
diff --git a/sample/https-client.c b/sample/https-client.c
index 81abc743..dfb77c66 100644
--- a/sample/https-client.c
+++ b/sample/https-client.c
@@ -16,7 +16,7 @@
 #include <string.h>
 #include <errno.h>
 
-#ifdef WIN32
+#ifdef _WIN32
 #include <winsock2.h>
 #include <ws2tcpip.h>
 #else