diff --git a/lib/world-map.js b/lib/world-map.js
index df9a8181..1a9e977b 100644
--- a/lib/world-map.js
+++ b/lib/world-map.js
@@ -68,6 +68,7 @@
  * @param {Function} params.onMarkerOut <code>(Event e, String code)</code> Will be called on marker mouse out event.
  * @param {Function} params.onMarkerClick <code>(Event e, String code)</code> Will be called on marker click event.
  * @param {Function} params.onMarkerSelected <code>(Event e, String code, Boolean isSelected, Array selectedMarkers)</code> Will be called when marker is (de)selected. <code>isSelected</code> parameter of the callback indicates whether marker is selected or not. <code>selectedMarkers</code> contains codes of all currently selected markers.
+ * @param {Function} params.onZoom <code>(Event e, Number scale)</code> Triggered the map is zoomed.
  */
 jvm.WorldMap = function(params) {
   var map = this,
@@ -442,7 +443,8 @@ jvm.WorldMap.prototype = {
   },
 
   setScale: function(scale, anchorX, anchorY, isCentered) {
-    var zoomStep;
+    var zoomStep,
+        viewportChangeEvent = jvm.$.Event('zoom.jvectormap');
 
     if (scale > this.params.zoomMax * this.baseScale) {
       scale = this.params.zoomMax * this.baseScale;
@@ -463,6 +465,9 @@ jvm.WorldMap.prototype = {
 
     this.scale = scale;
     this.applyTransform();
+
+    console.log(this.baseScale);
+    this.container.trigger(viewportChangeEvent, [scale/this.baseScale]);
   },
 
   /**
@@ -862,4 +867,5 @@ jvm.WorldMap.apiEvents = {
   onMarkerOut: 'markerOut',
   onMarkerClick: 'markerClick',
   onMarkerSelected: 'markerSelected',
+  onZoom: 'zoom'
 };
\ No newline at end of file
diff --git a/tests/markers.html b/tests/markers.html
index 848e7208..d414a311 100644
--- a/tests/markers.html
+++ b/tests/markers.html
@@ -134,6 +134,9 @@
               JSON.stringify(selectedRegions)
             );
           }
+        },
+        onZoom: function(e, scale){
+            console.log('viewportChange', scale);
         }
       });