diff --git a/lib/OpenLayers/Layer.js b/lib/OpenLayers/Layer.js
index 52339a0e3d..64e5bda570 100644
--- a/lib/OpenLayers/Layer.js
+++ b/lib/OpenLayers/Layer.js
@@ -29,6 +29,12 @@ OpenLayers.Layer = OpenLayers.Class({
      */
     div: null,
 
+    /**
+     * Property: opacity
+     * {Float} The layer's opacity. Float number between 0.0 and 1.0.
+     */
+    opacity: null,
+
     /** 
      * Constant: EVENT_TYPES
      * {Array(String)} Supported application event types
diff --git a/lib/OpenLayers/Layer/Markers.js b/lib/OpenLayers/Layer/Markers.js
index ba5b30592b..262fb123df 100644
--- a/lib/OpenLayers/Layer/Markers.js
+++ b/lib/OpenLayers/Layer/Markers.js
@@ -57,7 +57,22 @@ OpenLayers.Layer.Markers = OpenLayers.Class(OpenLayers.Layer, {
         OpenLayers.Layer.prototype.destroy.apply(this, arguments);
     },
 
-    
+    /**
+     * APIMethod: setOpacity
+     * Sets the opacity for all the markers.
+     * 
+     * Parameter:
+     * opacity - {Float}
+     */
+    setOpacity: function(opacity) {
+        if (opacity != this.opacity) {
+            this.opacity = opacity;
+            for (var i = 0; i < this.markers.length; i++) {
+                this.markers[i].setOpacity(this.opacity);
+            }
+        }
+    },
+
     /** 
      * Method: moveTo
      *
@@ -85,6 +100,11 @@ OpenLayers.Layer.Markers = OpenLayers.Class(OpenLayers.Layer, {
      */
     addMarker: function(marker) {
         this.markers.push(marker);
+
+        if (this.opacity != null) {
+            marker.setOpacity(this.opacity);
+        }
+
         if (this.map && this.map.getExtent()) {
             marker.map = this.map;
             this.drawMarker(marker);
diff --git a/tests/Layer/test_Markers.html b/tests/Layer/test_Markers.html
index 19612600b3..5b70308b1e 100644
--- a/tests/Layer/test_Markers.html
+++ b/tests/Layer/test_Markers.html
@@ -77,6 +77,32 @@
 
     }
 
+    function test_Layer_Markers_setOpacity(t) {
+        t.plan(1);
+
+        layer = new OpenLayers.Layer.Markers('Test Layer');
+
+        var opacity = 0.1234;
+        
+        for (var i = 0; i < 12; i++) {
+            layer.addMarker(new OpenLayers.Marker(new OpenLayers.LonLat(0,0), new OpenLayers.Icon()));
+        }
+
+        layer.setOpacity(opacity);
+
+        for (var i = 0; i < 4; i++) {
+            layer.addMarker(new OpenLayers.Marker(new OpenLayers.LonLat(0,0), new OpenLayers.Icon()));
+        }
+        
+        var itWorks = false;
+        for (var i = 0; i < layer.markers.length; i++) {
+            itWorks = parseFloat(layer.markers[i].icon.imageDiv.style.opacity) == opacity;
+            if (!itWorks) {
+                break;
+            }
+        }
+        t.ok(itWorks, "setOpacity change markers opacity");
+    }
 
   </script>
 </head>