The result of clinical survey of seventy-five children with supracondylar fractures of the humerus is presented. Sixty-eight fractures had gross displacement, and seven were undisplaced ones. Seven children with undisplaced fractures were treated with simple splinting. Twenty-one fractures with gross displacement were closedly reduced and immobilized by cast. Twenty cases treated with over-head skin traction or skeletal traction, and followed by cast immobilization, and twenty-seven were operatively reduced and were fixed with 2 K-wires. The results obtained were as follows: 1. The average age of children was 6.8 years, and the male and female ratio was 2.1:l. 2. 97.1% (66 cases) was the extension type and 2.9% (2 cases) was the flexion type. 3. Good end results were obtained in the well-reduced groups, such as undisplaced fractures and surgically reduced fractures. Of 27 operated cases, 19 who had early operation without manipulative trial or traction, had excellent results, while 8 who had surgery in delay developed limitation of flexion and/or extension motion of the elbow. Of these 19, two cases developed mild extension limitation as sequella. 4. As complications, incomplete ulnar nerve palsy developed in one case, but it spontaneously recovered in 3 weeks after open reduction. During treatment utilizing the olecranon pin traction, pin tract infection developed in 2 cases, but the infection was controlled by the antibiotic administration and wound dressing. Severe cubitus varus deformity developed in 4 cases among the conservatively treated group (manipulatively reduced group and skeletal traction group). These 4 children had corrective osteotomy. Mild deformity was the inevitable one when it is treated conservatively. Limitation of elbow motion developed in 23 cases (32%) as a sequella. 5. Fracture healed mostly in three weeks after reduction and immobilization. Average hospital stay for conservatively treated patients was 17.2 days, whereas that for surgically treated patients was 5.8 days in average. 6. Early anatomical reduction by any means whether it is surgical or nonsurgical, proved to be only the methods which bring the satisfactory results, and minimize the sequellae.