Purpose: We evaluated the complications of allograft reconstruction after a bone tumor resection, and reviewed literatures to overcome such complications. Materials and Methods: We retrospectively reviewed clinical records and radiographs of fifteen patients in whom reconstruction with allograft after bone tumor resection. Results: Eight patients were men and seven were women with a mean age of 27.1 years (1-56 years) and a mean follow-up period of 89.5 months (33-165 months). All postoperative complications related to the allograft were recorded. Twenty patients (80.0%) obtained a radiologic bony union at a mean of 8.35 months (4-12 months). The mean Musculoskeletal Tumor Society score was 73.5% (46.6-93.0%). Nine patients (60.0%) experienced one event and 3 (20.0%) patients experienced multiple events during the follow-up period. Recorded events were infection (3), fracture (2), nonunion (2), limb length discrepancy (2) and varus deformity (2). The mean event free survival period was 60.8 months (6-144 months). The mean allograft survival period was 80.2 months and the 5 year survival rate of the allografts was 83.0%. Conclusion: In order to overcome complications, the combination of an allograft and vascularized fibular graft is highly recommended. In the near future, the tissue engineering technique, the application of the stem cell and PRP, could reduce the complication of allograft such as resorption and nonunion.