Fresh allogenic mucosa lining the urinary bladder was transplanted into a 1 cm gap of right ulna bone in 24 guineapigs. The 1 cm, bone gap in the left ulna served as control. At regular intervals, the implanted and control sites were studied grossly with naked eye, radiologically and histopathologically to ascertain the role of allogenic vesical mucosa in inducing neo-osteogenesis. The bone gaps were uniformly bridged by bone in 10-12 wk at the implanted sites and fibrous tissue at control sites. There was no evidence of graft rejection. The study thus suggests the potential of the use of stored allogenic vesical mucosal grafts for neo-osteogenesis in clinical practice.