A canine model for cryopreservation and autotransplantation of parathyroid glands was developed as a prototype for cryopreservation of human parathyroid glands; Each of 18 dogs had two parathyroids removed, sectioned, and cooled at a controlled rate to -80 degrees in media containing 10% dimethylsulfoxide and 10% autologous serum. After storage for two months at -196 degrees the tissue was thawed and implanted in muscle; the remaining two parathyroid glands were removed from the neck. Function was assessed by monitoring serum calcium levels and measuring parathyroid hormone levels in venous effluent from the graft beds. Autograft function was demonstrated in ten of 18 dogs; graft failure occurred in four dogs. In the remaining four dogs, function could not be evaluated because of accessory parathyroid tissue. Parathyroid tissue cryopreserved for nine months was documented to function in six of seven dogs. Histologic study of the cryopreserved, autografted tissue showed normal parathyroid architecture.