diff --git a/mode/commonlisp/commonlisp.js b/mode/commonlisp/commonlisp.js
index 5b407a9285653846d50d86cb0580bf55fd400616..8cd212d3a8cda29a6571762dc399b182f053b610 100644
--- a/mode/commonlisp/commonlisp.js
+++ b/mode/commonlisp/commonlisp.js
@@ -43,7 +43,7 @@ CodeMirror.defineMode("commonlisp", function (config) {
       else { stream.skipToEnd(); return "error"; }
     } else if (ch == "#") {
       var ch = stream.next();
-      if (ch == "[") { type = "open"; return "bracket"; }
+      if (ch == "(") { type = "open"; return "bracket"; }
       else if (/[+\-=\.']/.test(ch)) return null;
       else if (/\d/.test(ch) && stream.match(/^\d*#/)) return null;
       else if (ch == "|") return (state.tokenize = inComment)(stream, state);