diff --git a/src/lang/string.js b/src/lang/string.js
index 844d6d9..5530ebb 100644
--- a/src/lang/string.js
+++ b/src/lang/string.js
@@ -39,6 +39,11 @@ Object.extend(String.prototype, (function() {
     var result = '', source = this, match;
     replacement = prepareReplacement(replacement);
 
+    if (!(pattern.length || pattern.source)) {
+      replacement = replacement('');
+      return replacement + source.split('').join(replacement) + replacement;
+    }
+
     while (source.length > 0) {
       if (match = source.match(pattern)) {
         result += source.slice(0, match.index);
diff --git a/test/unit/string_test.js b/test/unit/string_test.js
index ab20366..3590579 100644
--- a/test/unit/string_test.js
+++ b/test/unit/string_test.js
@@ -44,6 +44,11 @@ new Test.Unit.Runner({
       'ウィメンズ2007\nクルーズコレクション'.gsub(/\n/,'<br/>'));
     this.assertEqual('ウィメンズ2007<br/>クルーズコレクション', 
       'ウィメンズ2007\nクルーズコレクション'.gsub('\n','<br/>'));
+      
+    this.assertEqual('barfbarobarobar barbbarobarobar barbbarobarzbar',
+      source.gsub('', 'bar'));
+    this.assertEqual('barfbarobarobar barbbarobarobar barbbarobarzbar',
+      source.gsub(new RegExp(''), 'bar'));
   },
   
   testGsubWithReplacementTemplateString: function() {