diff --git a/src/prototype/ajax/ajax.js b/src/prototype/ajax/ajax.js
index e8b831abd..3f211e2e3 100644
--- a/src/prototype/ajax/ajax.js
+++ b/src/prototype/ajax/ajax.js
@@ -17,5 +17,6 @@ var Ajax = {
    *  Represents the number of active XHR requests triggered through
    *  [[Ajax.Request]], [[Ajax.Updater]], or [[Ajax.PeriodicalUpdater]].
   **/
-  activeRequestCount: 0
+  activeRequestCount: 0,
+  _jsonpfunctions: []
 };
diff --git a/src/prototype/ajax/request.js b/src/prototype/ajax/request.js
index 9bcd689ba..078079871 100644
--- a/src/prototype/ajax/request.js
+++ b/src/prototype/ajax/request.js
@@ -188,6 +188,16 @@ Ajax.Request = Class.create(Ajax.Base, {
       params += (params ? '&' : '') + "_method=" + this.method;
       this.method = 'post';
     }
+    if (this.options.jsonpparametername) {
+      this.method = 'get';
+      var currentfunctioncount = Ajax._jsonpfunctions.length;
+      Ajax._jsonpfunctions.push(function(data){
+        (this.options.onComplete || Prototype.emptyFunction)({'responseJSONP':data});
+        (this.options.onSuccess || Prototype.emptyFunction)({'responseJSONP':data});
+        $('AJAXJSONP_'+currentfunctioncount) ? $('AJAXJSONP_'+currentfunctioncount).remove() : '';
+      }.bind(this));
+      params += (params ? '&' : '') + this.options.jsonpparametername+'=Ajax._jsonpfunctions['+currentfunctioncount+']';
+    }
 
     if (params && this.method === 'get') {
       // when GET, append parameters to URL
@@ -196,6 +206,12 @@ Ajax.Request = Class.create(Ajax.Base, {
 
     this.parameters = params.toQueryParams();
 
+    if (this.options.jsonpparametername) {
+      document.body.insert(new Element('script',{'type':'text/javascript','src':this.url,'id':'AJAXJSONP_'+(Ajax._jsonpfunctions.length-1)}));
+      Ajax.Responders.dispatch('onCreate', this, response);
+      return;
+    }
+
     try {
       var response = new Ajax.Response(this);
       if (this.options.onCreate) this.options.onCreate(response);
diff --git a/test/unit/tests/ajax.test.js b/test/unit/tests/ajax.test.js
index caca3ee0d..5b4548079 100644
--- a/test/unit/tests/ajax.test.js
+++ b/test/unit/tests/ajax.test.js
@@ -477,6 +477,28 @@ suite("Ajax", function () {
 
     Ajax.Request.prototype.isSameOrigin = isSameOrigin;
   });
+  //
+  // Commented out because I'm not sure how to make WEBRICK and Sinatra handle this JSONP request
+  //
+  // test("JSONP with Same Origin",function(done){
+  //     new Ajax.Request("/jsonp",extendDefault({
+  //       parameters: "handlejsonp=1",
+  //       jsonpparametername:'callback',
+  //       onSuccess: function(transport) {
+  //         assert.equal(transport.responseJSONP.handlejsonp,"1");
+  //         done();
+  //       }
+  //     }))
+  // })
+  test("JSONP with Different Origin",function(done){
+      new Ajax.Request("http://echo.jsontest.com/key/value/one/two",extendDefault({
+        jsonpparametername:'callback',
+        onSuccess: function(transport) {
+          assert.deepEqual(transport.responseJSONP,{"one": "two","key": "value"});
+          done();
+        }
+      }))
+  })
 
 });