diff --git a/crypto/threads/mttest.c b/crypto/threads/mttest.c
index 01b587880..0ad8d0fe1 100644
--- a/crypto/threads/mttest.c
+++ b/crypto/threads/mttest.c
@@ -189,7 +189,7 @@ int main(int argc, char *argv[])
     SSL_CTX *c_ctx = NULL;
     char *scert = TEST_SERVER_CERT;
     char *ccert = TEST_CLIENT_CERT;
-    SSL_METHOD *ssl_method = TLS_method();
+    const SSL_METHOD *ssl_method = TLS_method();
 
     RAND_seed(rnd_seed, sizeof rnd_seed);