Unstable fractures of the distal radius continue to pose a challenge to the hand surgeon. Adjunctive bone grafting is often required to augment structural integrity and aid healing. Because of the risks inherent to bone autograft harvest, however, freeze-dried, irradiated cancellous bone allograft has been used to treat unstable distal radius fractures with severe metaphyseal comminution. Seventeen patients with such fractures (mean age, 70 years; 2 males and 15 females) were treated with bone allograft and external fixation with or without internal fixation. The outcome was evaluated using the modified Mayo wrist score, demonstrating 3 excellent, 8 good, 6 fair, and no poor results on follow-up examination (mean follow-up period, 23 months; range, 7-43 months). The patients were requested to return for follow-up review between 1997 and 1998. These results show that cancellous bone allograft is a useful adjunct to external fixation in the treatment of unstable distal radius fractures.