diff --git a/common/changes/office-ui-fabric-react/accContextualMenu_2018-02-03-00-25.json b/common/changes/office-ui-fabric-react/accContextualMenu_2018-02-03-00-25.json
new file mode 100644
index 00000000000000..5def6f81b68fdc
--- /dev/null
+++ b/common/changes/office-ui-fabric-react/accContextualMenu_2018-02-03-00-25.json
@@ -0,0 +1,11 @@
+{
+  "changes": [
+    {
+      "packageName": "office-ui-fabric-react",
+      "comment": "Contextual Menu - adding support for aria-setsize and aria-posinset for rendering menu items that relies on the menu item's own rendering",
+      "type": "patch"
+    }
+  ],
+  "packageName": "office-ui-fabric-react",
+  "email": "chiechan@microsoft.com"
+}
\ No newline at end of file
diff --git a/packages/office-ui-fabric-react/src/components/ContextualMenu/ContextualMenu.tsx b/packages/office-ui-fabric-react/src/components/ContextualMenu/ContextualMenu.tsx
index 2ab90b4c2c58c2..5a1916e8febf31 100644
--- a/packages/office-ui-fabric-react/src/components/ContextualMenu/ContextualMenu.tsx
+++ b/packages/office-ui-fabric-react/src/components/ContextualMenu/ContextualMenu.tsx
@@ -442,7 +442,7 @@ export class ContextualMenu extends BaseComponent<IContextualMenuProps, IContext
 
   private _renderNormalItem(item: IContextualMenuItem, classNames: IMenuItemClassNames, index: number, focusableElementIndex: number, totalItemCount: number, hasCheckmarks: boolean, hasIcons: boolean): React.ReactNode {
     if (item.onRender) {
-      return [item.onRender(item, this.dismiss)];
+      return [item.onRender({ 'aria-posinset': focusableElementIndex, 'aria-setsize': totalItemCount, ...item }, this.dismiss)];
     }
     if (item.href) {
       return this._renderAnchorMenuItem(item, classNames, index, focusableElementIndex, totalItemCount, hasCheckmarks, hasIcons);