diff --git a/lisp/mail/rmailsum.el b/lisp/mail/rmailsum.el
index 86a68457ada..5c5562ff604 100644
--- a/lisp/mail/rmailsum.el
+++ b/lisp/mail/rmailsum.el
@@ -1025,6 +1025,7 @@ Search, the `unseen' attribute is restored.")
   (define-key rmail-summary-mode-map "\M-u"   'rmail-summary-undelete-many)
   (define-key rmail-summary-mode-map "x"      'rmail-summary-expunge)
   (define-key rmail-summary-mode-map "w"      'rmail-summary-output-body)
+  (define-key rmail-summary-mode-map "v"      'rmail-mime)
   (define-key rmail-summary-mode-map "."      'rmail-summary-beginning-of-message)
   (define-key rmail-summary-mode-map "/"      'rmail-summary-end-of-message)
   (define-key rmail-summary-mode-map "<"      'rmail-summary-first-message)