Comminuted distal radial fractures with metaphyseal and diaphyseal extension are uncommon and remain a challenge to treat. The purpose of this study was to assess the radiographic and functional outcomes of treatment with the volar long locking compression plate (LCP) system for distal radius fractures with metaphyseal and diaphyseal extension. This retrospective study was performed on 22 consecutive patients who were treated with open reduction and internal fixation with the application of a 2.4-mm-extra-long LCP volar distal radius plate. Patients were evaluated based on clinical signs and radiography studies. The average time to fracture union was 16 weeks. The volar tilt was restored to a mean of 10.1°. The radial length and radial inclination were restored to a mean of 12.8 mm and 23.6° at final follow-up, respectively. The mean loss of radial length was -1.0 mm at final follow-up as compared with the contralateral extremity. The average ulnar variance was positive 0.1 mm at final follow-up with a congruent distal radioulnar joint. The degree of collapse after fixation between immediate postoperative and final follow-up visit was -0.1 mm. Using the demerit-point system of the Gartland and Werley rating system, 14 results were rated as excellent, 5 as good and 1 as fair. DASH scores averaged 10.1 points. Based on our experience, the volar long LCP is useful in the management of comminuted fractures of the distal radius, in which there is proximal extension into the diaphysis and can avoid or minimize the complications of external fixation or dorsal bridging distraction plate.