A backside illuminated image sensor and a method of manufacturing the same are disclosed. The backside illuminated image sensor includes a substrate having a frontside surface and a backside surface, pixel regions disposed in the substrate, an insulating layer disposed on the frontside surface of the substrate, a bonding pad disposed on a frontside surface of the insulating layer, a second bonding pad connected to a backside surface of the bonding pad through the substrate and the insulating layer and exposed through the backside surface of the substrate, and a test pad connected to the backside surface of the bonding pad through the substrate and the insulating layer, exposed through the backside surface of the substrate, and for testing whether the second bonding pad is normally connected to the backside surface of the bonding pad.