An automatic cable tie installation tool for applying discrete cable ties around bundles of wires or the like where the cable ties are provided to the tool on a continuous ribbon. The automatic tool including a dispenser mechanism that accepts the ribbon of cable ties and provides discrete cable ties therefrom; a tool mechanism that positions the discrete cable tie around the bundle of wire, tensions the tie to a preselected value and severs the tail of the cable tie; and a conveyance mechanism that delivers the cable tie provided by the dispenser mechansim to the tool mechanism. The dispenser mechanism including a reel mechanism for providing the cable tie ribbon to the dispenser mechanism, a grooved cylinder that carries individual cable ties for positioning and translating the ribbon longitudinally, an index mechanism for rotating the cylinder in accurate increments, a mechanism for separating individual cable ties from the ribbon, a guide mechanism for positioning the ribbon laterally relative to the separation means and a mechanism for transferring the separated cable ties to the conveyance mechanism. The ribbon includes a strip portion extending the length of the ribbon having a plurality of cable ties connected thereto by respective connecting tabs. The strip portion having an alignment mechanism adapted to cooperate with the guide mechanism in the dispenser to accurately position the ribbon laterally in the dispenser mechanism.