diff --git a/lib/nodes.js b/lib/nodes.js
index b93ca09d..602eb0cd 100644
--- a/lib/nodes.js
+++ b/lib/nodes.js
@@ -1886,7 +1886,7 @@
   TRAILING_WHITESPACE = /[ \t]+$/gm;
   IDENTIFIER = /^[a-zA-Z\$_](\w|\$)*$/;
   NUMBER = /^(((\b0(x|X)[0-9a-fA-F]+)|((\b[0-9]+(\.[0-9]+)?|\.[0-9]+)(e[+\-]?[0-9]+)?)))\b$/i;
-  SIMPLENUM = /^-?\d+/;
+  SIMPLENUM = /^-?\d+$/;
   IS_STRING = /^['"]/;
   literal = function(name) {
     return new LiteralNode(name);
diff --git a/src/nodes.coffee b/src/nodes.coffee
index 0dd4b957..e2b56290 100644
--- a/src/nodes.coffee
+++ b/src/nodes.coffee
@@ -1605,7 +1605,7 @@ TRAILING_WHITESPACE = /[ \t]+$/gm
 # Keep these identifier regexes in sync with the Lexer.
 IDENTIFIER = /^[a-zA-Z\$_](\w|\$)*$/
 NUMBER     = /^(((\b0(x|X)[0-9a-fA-F]+)|((\b[0-9]+(\.[0-9]+)?|\.[0-9]+)(e[+\-]?[0-9]+)?)))\b$/i
-SIMPLENUM  = /^-?\d+/
+SIMPLENUM  = /^-?\d+$/
 
 # Is a literal value a string?
 IS_STRING = /^['"]/