Objective To study cl inical effects of the graft material of allogenic cancellus combined with autologousred marrow in the treatment of traumatic bone defect. Methods From February 2002 to April 2006, 38 patients of traumaticbone defect, 25 males and 13 females, aged 21-68 years old (38 on average), were treated with allogenic cancellus combined with autologous red marrow. Among them, there were 11 cases of bone nonunion caused by failure of internal fixation, 13 of serious comminuted fracture, 9 of bone defect caused by open fractures or bone infection, 5 of old fracture in need of graft. Of these fractures, there were 8 cases of shaft of humerus, 4 of intercondylar comminuted fracture of humerus, 8 of intercondylar comminuted fracture of femur, 5 of shaft of femur, 4 of open tibia fracture (Gustilo I, II type) and 9 of tibial plateau fracture. They included 17 cases of fresh fracture and 21 of old fracture. There were 23 cases of l imitations of bone defect, and the range was 3 cm × 3 cm × 2 cm - 7 cm × 4 cm × 3 cm; and the range of the large bone defect was less than 3 cm in 15 cases. According to AO/ASIF classification, there were 5 cases of type B2, 10 of type B3, 16 of type C2 and 7 of type C3. The time from fresh fracture to operation was 5-17 days (8 days on average), and the time from old fracture to operation was 5-13 months (7.5 months on average). The amount of the allograft implantation was 20-50 g (28 g on average). Results The wounds in all 38 cases obtained heal ing by first intention. All the patients were followed up for 8 months to 4 years (3.2 years on average). The X-ray films at reexamination showed that 36 patients had bone heal ing, with fresh fracture heal ing time of 2-6 months (4 months on average) and old fracture heal ing time of 3-10 months (7 months on average). The allogenic cancellus particles began to be fused with autogenous bone through creeping substitution 6-8 weeks after operation. One case, which had delayed infection, had bone union by removing internal fixation, placing irrigating tube and grafting after local stabil ity. During the follow-up of 25 months, no relapse was found. Another case had nonunion because of plate loosening. According to the Mankin and Komender standard evaluation, there were 36 cases with satisfaction (94.7%) and 2 with dissatisfaction (5.3%). Conclusion The composite graft material of allogenic cancellus combined with autologous red marrow is safe and effective for repairing fractures and bone defect.