A tibial segment in 3cm length with vascular pedicle and periosteum (Living bone graft) and the segment without vascular pedicle and periosteum (Dead bone graft) was obtained from twenty four rabbits, being divided into two group respectively. Then it was replaced with the segmental bone in the initial osteomized defect. The grade of healing and the time factor required to accomplish the repair of resected segmental tibial transplant was determined at one week interval during one to eight weeks, aimed by the,comparative studies of microscopic (gross), radiological as well as histological observation during the healing process. The average time of callus formation in the living bone graft was approximately two weeks, as compared to four weeks of the dead bone graft. Radiographically the average time of bone union in the living bone graft was four weeks, compared with seven weeks for the dead bone graft. The living bone graft was permitted to the healing process of the simple fracture at the graft-recipient bone juncture, in the contrast with the dead bone graft it was united with replacement of the grafted bone by new bone, so called “creeping substitution”.