PURPOSE: The current study was performed to evaluate the treatment and functional results of the three and four part fractures of proximal humerus. MATERIALS AND METHODS: Nineteen patients with displaced 3 part and 4 part fractures and fractures-dislocation were followed for more than one year and analyzed. The causes of injuries, classification of fracture, associated injuries, functions, results of treatment and complications were investigated. RESULTS: According to Neer's classification, there were 15 cases of 3 part fracture and 4 cases of 4 part fractures. The range of motion and functional results of the shoulder in 3 part fractures (flexion 138.6degrees , abduction 124.3degrees , Constant score 60.3) were better than 4 part fractures (flexion 77.5degrees , abduction 60degrees , Constant score 29.5). We compared the humeral offset of injured side with the healthy one. In the cases of less than 4mm difference, the range of motion was 150degrees in flexion and 40.3degrees i n abduction, and the constant score was 67.3. But in the cases of more than 4mm difference, the range of motion was 84.3degrees in flexion and 58.6degrees in abduction, and constant score was 30.9 points. Clinical results was better in the cases of less than 4mm difference. CONCLUSION: Range of motion and functional results of 3 part fractures were better than 4 part fractures and restoration of humeral offset resulted in better clinical results.