Abstract: In apparatus for applying a two-part surgical fastener including a fastener part having at least one prong and a retainer part having an aperture for receiving and retaining the distal end of the prong, the retainer part is initially held securely to the apparatus by contact with a lug extending into the aperture. The lug is connected to the structure which supports the retainer part of the fastener by a frangible member. When the two parts of the fastener are forced together, the distal end of the prong pushes the lug out of the aperture, thereby breaking the frangible member and releasing the retainer part from the apparatus. The breaking of the frangible member preferably provides the operator of the apparatus with an indication that the two parts of the fastener have interlocked. This indication may be either tactile or audible or both.