Disclosed is a cassette loading system in a housing having an aperture which delivers a plurality of cassettes one cassette at a time into a cassette drive. The system includes a cassette drive having a cassette acceptor and a cassette magazine mounted through the aperture. The magazine defines a plurality of spaces, with each of the plurality of spaces sized and shaped to receive a cassette. The magazine is also adjustable within the aperture to align each of the plurality of spaces with the cassette acceptor of the drive. The system also include a cassette transfer system which moves each of the cassettes into the acceptor of the drive and retracts each of the cassettes upon ejection by the drive. The transfer system includes a cassette transfer motor which is activated to cause motion which moves a cassette into and out of the acceptor, a plurality of cassette drive wheels which can engage a cassette to move the cassette into the acceptor of the drive and to retract a cassette upon ejection by the drive and an engagement assembly which is activated in order to engage the drive wheels with a cassette in order to move a cassette into the acceptor or to retract a cassette upon ejection by the drive. An engagement assembly for a loader is also disclosed. Additionally, there is disclosed a method of sequentially loading cassettes into a tape drive system using the novel cassette loading system.