ANGIOTENSIN II is an important effector molecule controlling blood pressure and volume in the cardiovascular system¹. Its importance is manifested by the efficacy of angiotensin-converting enzyme inhibitors in the treatment of hypertension and congestive heart failure^2,3. Angiotensin II interacts with two pharmacologi-cally distinct subtypes of cell-surface receptors, AT₁ and AT₂ (ref. 4). AT₁ receptors seem to mediate the major cardiovascular effects of angiotensin II^5,6. Here we report the isolation by expression cloning of a complementary DNA encoding a unique protein with the pharmacological specificity of a vascular AT₁ receptor. Hydropathic modelling of the deduced protein suggests that it shares the seven-transmembrane-region motif with the G protein-coupled receptor superfamily⁷. Knowledge of the AT₁ receptor primary sequence should now permit structural analysis, definition of the angiotensin II receptor gene family and delineation of the contribution of AT receptors to the genetic component of hypertension.