diff --git a/rev-list.c b/rev-list.c
index d836feb86a..17995c34c4 100644
--- a/rev-list.c
+++ b/rev-list.c
@@ -63,7 +63,8 @@ static void show_commit(struct commit *commit)
 		static char pretty_header[16384];
 		pretty_print_commit(commit_format, commit->buffer, ~0, pretty_header, sizeof(pretty_header));
 		printf("%s%c", pretty_header, hdr_termination);
-	}	
+	}
+	fflush(stdout);
 }
 
 static int filter_commit(struct commit * commit)