diff --git a/lisp/erc/erc-services.el b/lisp/erc/erc-services.el
--- a/lisp/erc/erc-services.el
+++ b/lisp/erc/erc-services.el
@@ -303,7 +303,10 @@ The last two elements are optional."
 		 (boolean :tag "Use current nick in identify message?")
 		 (choice :tag "Command to use (optional)"
 		  (string :tag "Command")
-		  (const :tag "No special command necessary" nil)))))
+		  (const :tag "No special command necessary" nil))
+		 (choice :tag "Detect Success"
+		  (regexp :tag "Pattern to match")
+		  (const  :tag "Do not try to detect success" nil))) ))
 
 (defsubst erc-nickserv-alist-sender (network &optional entry)
   (nth 1 (or entry (assoc network erc-nickserv-alist))))