PURPOSE: We compared the functional and radiological results after the minimal open reduction and interlocking IM nailing and LC-DCP plate internal fixation for the comminuted humeral shaft fractures. MATERIALS AND METHODS: Fourteen plates(LC-DCP) and eighteen interlocking IM nail(AO unreamed IM nail) were applied after open reduction for 32 comminuted fractures of the humeral shaft between March 1997 and December 2001. They were followed up for a minimum 9 months after surgery and the radiological and functional results were evaluated. RESULTS: The average fracture healing time was 13.2 weeks and union rate was 85.7% for plate internal fixation. The average fracture healing time was 12.4 weeks and union rate was 94,4% for interlocking IM nail. The average functional scores according to American Shoulder and Elbow Surgeon 's (ASES) shoulder score(Total 52 points) was 44 points for plate internal fixation and 47 points for interlocking IM nailing respectively. CONCLUSION: Minimal open reduction and interlocking IM nailing is better method with good functional and radiological results than plate internal fixation for the comminuted humeral shaft fractures.