PURPOSE: To analyze radiological and functional results after open reduction and internal fixation for fractures of the neck of humerus (4-part) using cannulated screws. MATERIAL AND METHODS: Between January 1997 and April 2004, 11 patients with neck of humerus fracture (4-part) were treated operatively by open reduction and internal fixation with cannulated screws. Two surgical approaches (deltopectoral for 9 cases and deltoid splitting for 2 cases) were used. The mean age was 36 years old and the mean duration of follow-up was 56 months. ASES (American Shoulder and Elbow Surgeons) score was checked to evaluate the function in shoulder joint. We used 2 cannulated screws in 2 cases, 3~4 screws in 6 cases and over 5 screws in 3 cases for fixation. In 2 cases, K-wires were used additionally and autoiliac bone graft was done in 1 cases which had poor bone mass. RESULTS: All cases got bony union at 5.6 months on average. In functional assessment of shoulder, eight patients got excellent, one got good points. There were complications including shoulder stiffness in 2 cases, avascular necrosis of humeral head in 1 case and subacromial impingement syndrome in 1 case. CONCLUSION: Internal fixation using cannulated screws for fractures of humerus neck (4 part) showed good bony union and functional results in patients under 50 years old who had average bone quality.