Experience with 8 patients undergoing aortic vascular pedicle transplantation of neonatal parathyroid tissue showed clinical improvement of post-thyroidectomy tetany despite adequate histologic evidence of graft rejection in 2 patients. The rejection of neonatal tissue was due to classical homograft rejection mechanisms. The permanency of postthyroidectomy hypoparathyroidism may he related in part to the suppressive effect of calcium therapy upon residual parathyroid gland remnants. Reduction of calcium therapy following parathyroid gland homotransplantation may allow resumption of function of such remnants.