PURPOSE: To evaluate the significance of distal radioulnar joint injury which may affect the postoperative radiologic and clinical results of AO classification, type C distal radius fractures. MATERIALS AND METHODS: From October 2000 to October 2005, 58 patients of AO classification, type C distal radius fracture, who had been treated with operative methods were studied. They are thirty-six men and twenty-two women. The average follow up period was 14 months. The patients were divided into five groups. In the first group (13 cases), there was no distal radioulnar joint injuries. In the second group (20 cases), there were ulnar styloid fractures. In the third group (11 cases), there were separation of distal radioulnar joint. In the fourth group (9 cases), there were ulnar styloid fractures with separation of distal radioulnar joint. In the fifth group (5 cases), there were displacement of ulna in sagittal plane. We measured the radial length, radial inclination and volar tilt in plain radiograph in each group and analyzed the results through Scheck's methods. To analyzed the clinical results, we used the Demerit Point System by Sarmiento. RESULTS: There was no significant differences in radiologic and clinical results among the five groups. CONCLUSION: According to compairing the radiologic results of each group which was suspicious of distal radioulnar joint injuries, in the intraarticular comminuted fractures of distal radius, the distal radioulnar joint injuries did not affect the results of treatment when anatomical reduction of distal radius was achieved.