diff --git a/src/mars.d b/src/mars.d
index ecd3e41e2c2a..b5fa9955ae36 100644
--- a/src/mars.d
+++ b/src/mars.d
@@ -264,6 +264,7 @@ extern (C++) int tryMain(size_t argc, const(char)** argv)
     debug
     {
         printf("DMD %s DEBUG\n", global._version);
+        fflush(stdout); // avoid interleaving with stderr output when redirecting
     }
     unittests();
     // Check for malformed input