diff --git a/src/leaflet.groupedlayercontrol.js b/src/leaflet.groupedlayercontrol.js
index 95a3b35..ff73ea6 100644
--- a/src/leaflet.groupedlayercontrol.js
+++ b/src/leaflet.groupedlayercontrol.js
@@ -66,7 +66,7 @@ L.Control.GroupedLayers = L.Control.extend({
     var id = L.Util.stamp(layer);
     var _layer = this._getLayer(id);
     if (_layer) {
-      delete this.layers[this.layers.indexOf(_layer)];
+      delete this._layers[this._layers.indexOf(_layer)];
     }
     this._update();
     return this;