Peroneus brevis tendon transfer has been utilized in 40 individuals during the last 13 years. All cases consisted of complete Achilles tendon ruptures. In 34 cases the rupture was in the distal one-third of the tendon substance, in four cases bony avulsion of the calcaneal tuberosity occurred, and in two cases there was a diffuse tear in the proximal two-thirds of the tendon near the musculotendinous junction. The middle-aged athlete sustained the majority of these injuries during sports. Eleven patients were less than 30 years old, 23 patients were 30 to 40 years old, and six were over 40 years old. Five patients had reruptures that involved prior nonoperative treatment of cast immobilization, and one had undergone simple direct suture. This repair has been used in acute, chronic, and recurrent ruptures of the tendoachillis. Thirty-three patients presented within 1 week of injury, and seven after more than 1 week. A. Perez Teuffer personally described the preferred technique in 1971 and subsequently published in 1978. The transfer of the peroneus brevis is combined with a direct end-to-end suture of the triceps surae tendon that allows a secure reconstruction with the foot at a right angle. The peroneus brevis tendon is detached from the base of the fifth metatarsal and then tunnelled through the distal Achilles tendon stump. The distal portion of the tendon transfer is then drawn proximally along the medial calcaneal tendon border. The proximal triceps surae tendon is pulled distally and secured to the peroneal tendon.(ABSTRACT TRUNCATED AT 250 WORDS)