diff --git a/demos/callbacks.htm b/demos/callbacks.htm
index 234977d..e29c7f6 100644
--- a/demos/callbacks.htm
+++ b/demos/callbacks.htm
@@ -32,9 +32,15 @@
 		close: function(){
 			$callback.text("Select closed!");
 		},
+		beforeCheckAll: function(){
+			$callback.text("Before Check all click event!");
+		},
 		checkAll: function(){
 			$callback.text("Check all clicked!");
 		},
+		beforeUncheckAll: function(){
+			$callback.text("Before Uncheck all click event!");
+		},
 		uncheckAll: function(){
 			$callback.text("Uncheck all clicked!");
 		},
@@ -94,9 +100,15 @@ <h2>Callbacks &amp; Events</h2>
    checkAll: function(){
       $callback.text("Check all clicked!");
    },
+   beforeCheckAll: function(){
+      $callback.text("Before Check all click event!");
+   },
    uncheckAll: function(){
       $callback.text("Uncheck all clicked!");
    },
+   beforeUncheckAll: function(){
+      $callback.text("Before Uncheck all click event!");
+   },
    optgrouptoggle: function(event, ui){
       var values = $.map(ui.inputs, function(checkbox){
          return checkbox.value;
diff --git a/src/jquery.multiselect.js b/src/jquery.multiselect.js
index a1cd9e4..fb45fd1 100644
--- a/src/jquery.multiselect.js
+++ b/src/jquery.multiselect.js
@@ -625,11 +625,13 @@
     },
 
     checkAll: function(e) {
+      this._trigger('beforeCheckAll');
       this._toggleChecked(true);
       this._trigger('checkAll');
     },
 
     uncheckAll: function() {
+      this._trigger('beforeUncheckAll');
       this._toggleChecked(false);
       this._trigger('uncheckAll');
     },