diff --git a/scheme/httpd/cgi-server.scm b/scheme/httpd/cgi-server.scm
index f9a9b75..8882453 100644
--- a/scheme/httpd/cgi-server.scm
+++ b/scheme/httpd/cgi-server.scm
@@ -237,6 +237,7 @@
 ;;; it into a real HTTP response, which we then send back to the HTTP client.
 
 (define (cgi-make-response script-port path req)
+  (set-port-buffering script-port bufpol/block 4096)
   (let* ((headers (read-rfc822-headers script-port))
 	 (ctype (get-header headers 'content-type))
 	 (loc   (get-header headers 'location))
@@ -271,7 +272,7 @@
 	 extra-headers
 	 (make-writer-body
 	  (lambda (out options)
-	    (copy-inport->outport script-port out)
+	    (copy-inport->outport script-port out 4096)
 	    (close-input-port script-port)))))))
 
 (define (delete-headers headers tag)