Free autologous muscle transplants, as described by Noel Thompson, were performed on 15 Vietnamese pigs for reconstruction of partly destroyed sphincter ani externus in two series of 10 and 5 animals. In the first series, a 1.5 cm resection, in the second series a semi-circumferential resection of the muscle sphincter ani externus was bridged by a muscle transplant from the front leg of the pig 14 days after a denervation was performed. Six months later all transplants were re-opened and showed in seven cases of the first series a perfect muscle quality morphologically as well as functionally. In the second series the area of muscle which was not in contact with the underlying sphincter muscle showed a marked fibrous change.