THE neurohypophyseal hormone arginine vasopressin has diverse actions^1–7 , including the inhibition of diuresis, contraction of smooth muscle, stimulation of liver glycogenolysis and modulation of adrenocorticotropic hormone release from the pituitary. Arginine vasopressin receptors are G protein-coupled and have been divided into at least three types⁸; the Via (vascular/hepatic)^1,9–11and Vlb (anterior pituitary)¹² receptors which act through phosphatidylinositol hydrolysis to mobilize intracellular Ca²⁺, and the V2 (kidney) receptor^1,13,14which is coupled to adenylate cyclase. We report here the cloning of a complementary DNA encoding the hepatic Via arginine vasopressin receptor. The liver cDNA encodes a protein with seven putative transmembrane domains, which binds arginine vasopressin and related compounds with affinities similar to the native rat Via receptor. The messenger RNA corresponding to the cDNA is distributed in rat tissues known to contain Via receptors.