Abstract: A mechanism packaging tape cassettes in cardboard sleeves including a controlled cassette guideway which advances cassettes to a packaging station and a controlled loading track which advances sleeves to the packaging station for positioning on the cassettes. The guideway may either receive cassettes from an incoming belt or a hopper. A pusher mechanism advances the cassettes to the packaging station while a retractable stop insures proper location of the cassette. The cassette is slightly raised above the surface of the guideway to be properly positioned for receiving the enclosing sleeve. The loading track includes a hopper to receive collapsed sleeves. The sleeves are released one-at-a-time into the loading track where a sleeve pusher advances the sleeves one-at-a-time into a die defined by opposed channels. The channels are spaced such that the continued pushing of the sleeve therethrough causes it to assume its appropriate rectangular configuration.