The significance of the beta adrenergic system in the nasal mucosa isunclear. The authors have used the technique of autoradiography to localize and classify beta adrenoceptors in human nasal mucosa. The receptors have been found to beexclusively of thebeta-2 subtype and the highest density is found in the glandularducts. It is suggested that the beta-adrenergic system may have a physiologically important role in controlling the electrolyte composition of nasal secretions.