diff --git a/crypto/threads/mttest.c b/crypto/threads/mttest.c
index 8f67db6ee..0c6ada219 100644
--- a/crypto/threads/mttest.c
+++ b/crypto/threads/mttest.c
@@ -107,7 +107,7 @@
 
 #define MAX_THREAD_NUMBER       100
 
-int MS_CALLBACK verify_callback(int ok, X509_STORE_CTX *xs);
+int verify_callback(int ok, X509_STORE_CTX *xs);
 void thread_setup(void);
 void thread_cleanup(void);
 void do_threads(SSL_CTX *s_ctx, SSL_CTX *c_ctx);
@@ -640,7 +640,7 @@ int doit(char *ctx[4])
     return (0);
 }
 
-int MS_CALLBACK verify_callback(int ok, X509_STORE_CTX *ctx)
+int verify_callback(int ok, X509_STORE_CTX *ctx)
 {
     char *s, buf[256];