diff --git a/apps/speed.c b/apps/speed.c
index ce01a6f3c0d56db3a01b4ee830d2109fd4d16584..0c996f070c4895490436f14a15b8330d26cd8205 100644
--- a/apps/speed.c
+++ b/apps/speed.c
@@ -1431,6 +1431,12 @@ int speed_main(int argc, char **argv)
             break;
         case OPT_MB:
             multiblock = 1;
+#ifdef OPENSSL_NO_MULTIBLOCK
+            BIO_printf(bio_err,
+                       "%s: -mb specified but multi-block support is disabled\n",
+                       prog);
+            goto end;
+#endif
             break;
         }
     }