The treatment of Achilles tendon rupture is controversial between surgical repair and conservative cast treatment. Until the 1970s, treatment of Achilles tendon rupture was predominantly surgical repair, but Lea and Smith reported better results in conservative treatment of Achilles tendon rupture and other authors confirmed their good results with cast treatment. This study was attempted to compare the subjective and objective results between operative and conservative treatments of patients with ruptured Achilles tendon. In a retrospective study, 30 Patients with ruptured Achilles tendon were analyzed from January 1990 to May 1994. 15 patients were surgically repaired(group I), and 15 patients were treated with gravity equines short leg walking cast(group II), Patient's subject satisfaction, duration from trauma to normal activity level, plantar flexion power, tendinous healing state checked by ultrasonography, and complications were compared, and following results were obtained. 1. All patients satisfied with conservative treatment in group II, while 12 patients were satisfied with operative treatment in group I. 2. The plantar flexion power of injured side was 89% in group I, 87% in group II comparing with uninjured side. 3. Ultrasonographically, mean thickness and ruptured midportion thickness in group II was thicker than those of group I(8.7, 10.6 vs 9.2, 13.2mm), but focal sonolucent area which indicates incomplete healing was observed more in group II than in group I(4 vs 2). 4. Three patients had complications in group I-1rerupture, 1 infection and 1 sural nerve injury.