diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index eaf7c4653af..5c72fbdf291 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,8 @@
+2015-03-20  Dmitry Gutov  <dgutov@yandex.ru>
+
+	* progmodes/ruby-mode.el (ruby-syntax-before-regexp-re): Detect
+	regexps after `!'.  (Bug#19285)
+
 2015-03-20  Dmitry Gutov  <dgutov@yandex.ru>
 
 	* progmodes/ruby-mode.el (ruby-font-lock-keywords): Use
diff --git a/lisp/progmodes/ruby-mode.el b/lisp/progmodes/ruby-mode.el
index e15105eb332..39c9ca0d771 100644
--- a/lisp/progmodes/ruby-mode.el
+++ b/lisp/progmodes/ruby-mode.el
@@ -1777,7 +1777,7 @@ It will be properly highlighted even when the call omits parens.")
   (defvar ruby-syntax-before-regexp-re
     (concat
      ;; Special tokens that can't be followed by a division operator.
-     "\\(^\\|[[{|=(,~;<>]"
+     "\\(^\\|[[{|=(,~;<>!]"
      ;; Distinguish ternary operator tokens.
      ;; FIXME: They don't really have to be separated with spaces.
      "\\|[?:] "