diff --git a/crypto/internal.h b/crypto/internal.h
index 714f207..2229e19 100644
--- a/crypto/internal.h
+++ b/crypto/internal.h
@@ -188,7 +188,7 @@
 #endif
 
 
-#if !defined(_MSC_VER)
+#if !defined(_MSC_VER) && defined(OPENSSL_64_BIT)
 typedef __int128_t int128_t;
 typedef __uint128_t uint128_t;
 #endif