Background/Aims: A 50-year-old type 2 diabetic male with a comminuted fracture of the tibia and delayed union after insufficient initial osteosynthesis with a resulting pseudoarthrosis was treated operatively by using a graft composed of platelet gel mixed with autologous cancellous bone. The essential idea of this therapy was to combine the healing capacities of platelet-derived growth factors and osteogenic stem cells and the modeling capacity of the gel. Due to a history of diabetes, allogeneic instead of autologous platelets were used. Methods: The allogeneic platelet concentrate was ABO- and RhD-matched, leukocyte-depleted, irradiated and activated by human thrombin. The defect of 45 ml was filled with the graft mixture and fixed with an external fixator. Results: Postoperative care was uneventful. After 6 months the graft was incorporated, the bone defect was fully bridged and full weight-bearing capacity was achieved. No side effects were observed and no platelet or HLA class I antibodies were detected. Conclusion: This case report shows that the clinical use of allogeneic platelet-derived growth factors is feasible and that a prospective study is necessary to prove the effectiveness and reproducibility of this therapeutic approach.