Achilles tendon is the most powerful and the biggest tendon of the body and its rupture is frequently sports-related. Many authors reported the effects of mobilization, electricity, ultrasound and various drugs as factors influencing the injured tendon. We studied the effects of early passive mobilization after firm suture using plantaris tendon as tension suture material and reinforcing membrane on the repair of a ruptured Achilles tendon. From March 1992 to December 1995, twenty-two operations on the Achilles tendon were carried out in our hospital. 1. Fourteen patients were male and eight patients were female. The mean patient age was 38 years, ranging from 13 to 68 years. Average follow-up periods was 2 years and 7 months, ranging from 12 months to 3 years and 8 months. 2. The rupture site was 4.7cm proximal to the tendon insertion into the calcaneus on average. 3. We performed the operations with end to end suture technique. After approximation of the ruptured ends of the tendon with a No. 5 Ethibond tension suture using a modified Kessler stitch, placed plantaris tendon in a fascial needle and pass it circumferentially and distal plantaris tendon is fanned out and tacked over the repair. 4. Postoperative treatment was done as following protocol Short leg cast was done with equinus position for initial 3 weeks, and then cast was removed, hydrotherapy and passive exercises was employed. About 6 weeks after operation when the foot can be brought to right angle, a reverse 90degrees ankle stop short leg brace was applied for additional 6 weeks and partial weight bearing was aUowed. 5. Follow-up results were classified according to the Arner-Lindholm scale. We had 16 excellent results and 6 satisfactory results. After rigid suture it may be possible to introduce a regimen of progressive isometric stimulation and protected loading and streching combined with removable orthosis. Such early exercises are likely to improve the rate of rehabilitation over plaster immobilization.