diff --git a/simple.scm b/simple.scm
index dad662f..704f07a 100644
--- a/simple.scm
+++ b/simple.scm
@@ -215,7 +215,8 @@
   (printf "~X" (string-length contents))
   (display "\n")
   (display contents)
-  (display "\n"))
+  (display "\n")
+  (flush-output (response-port (current-response))))
 
 (define (define-page path contents #!key css title doctype headers charset
           (method 'GET) use-session) ;; for define-session-page