The knee joint is the largest weight bearing joint. Knee joint fractures involve the articular surface and damage the surrounding soft tissues, and permanent deformities, especially joint stiffness, instability of the knee joint, post-traumatic arthritis, etc, may ensue following treatment. Many authors have recommended various methods of treatment for these fractures, This study is to present 77 cases of knee joint fractures which were treated at Severance Hospital from January 1965 to December 1974. The results of clinical study were as follows: 1. The causes of injury were traffic accident(75.3%), falling(15.6%) and direct blow(9.1%). 2. There were 63 males and 14 females in the series, 3. Age span was generally 10~40 Years. 4. Among the 77 cases, 42 were femoral condylar fractures, 28 were tibial condylar fractures, and 7 were tibial spine fractures. 5. In femoral condylar fractures, 27 cases were treated by conservative method and 13 cases underwent open reduction, and the clinical end results were satisfactory in 79.2% by conservative method and 54.5% by operative treatment. 6. In tibial condylar fractures, 14 cases were treated by conservative method and 12 cases by operation. Satisfactory results were obtained in 66.7% by conservative treatment and in 72.7% by operation.