The location of beta-adrenoceptors in human parathyroid gland was studied using an immunohistochemical method. Frozen sections of human parathyroid glands, taken from surgical samples, were treated with (-)-alprenolol, washed and exposed to (-)-alprenolol antibodies conjugated with fluorescent dyes. The (-)-alprenolol was bound to the parathyroid principal cells and to the main blood vessels. On the contrary, adrenergic nerve fibres, demonstrated with formaldehyde fluorescence technique, were only located within the walls of main blood vessels. The findings are discussed.