Laryngeal allograft transplantation was performed with vascularized pedicle and cyclosporine A was administrated for prevention of graft rejection and the result was compared with the control study which was an autograft to the same location ; the lateral neck. 1) There was no tissue rejection and minimal inflammatory reaction in the autograft, wherease in 7 cases out of 8(87.5%) allografts, a varing degree of rejection was observed. 2) At the first week of acute rejection, partial destructed of mucosa, submucosal edema and infiltration of inflammatory cells were the typical findings. At the second week, total loss of lining epithelial cells with the destruction of minor salivary glands and cartilage were observed. 3) Findings of chronic rejection, at the eighth week, the larynx has collapsed by destruction of its cartilagenous supporting framework and fibrosis occurred. At the twelfth week, necrosis of vessel wall with neovascular proliferation was observed. Laryngeal allograft transplantation in cats showed many limitations in preserving its morphologic and functional characteristics because of the donor tissue rejection, but if only the tissue rejection problem is solved, allograft transplantation would be feasible.