diff --git a/multiple-cursors-core.el b/multiple-cursors-core.el
index 886d86d..b6ab255 100644
--- a/multiple-cursors-core.el
+++ b/multiple-cursors-core.el
@@ -402,7 +402,9 @@ multiple cursors editing.")
   (define-key mc/keymap (kbd "C-g") 'mc/keyboard-quit)
   (define-key mc/keymap (kbd "<return>") 'multiple-cursors-mode)
   (when (fboundp 'phi-search)
-    (define-key mc/keymap (kbd "C-s") 'phi-search)))
+    (define-key mc/keymap (kbd "C-s") 'phi-search))
+  (when (fboundp 'phi-search-backward)
+    (define-key mc/keymap (kbd "C-r") 'phi-search-backward)))
 
 (defun mc--all-equal (entries)
   "Are all these entries equal?"