A cDNA encoding a chicken angiotensin II receptor from adrenal gland was isolated to serve as a molecular tool to study the role of AngII in avian embryonic development. This cDNA, sharing a high homology with another avian receptor (turkey), encodes a protein of 359 amino acids with 75% sequence identity with the mammalian type 1 receptor. Transient expression has revealed pharmacological properties distinct from mammalian receptors and a functional coupling leading to the increase in inositol phosphate production. The AngII receptor mRNA is expressed in classical target organs for AngII (adrenal gland, heart, kidney) and, interestingly, in endothelial cells where it may mediate the peculiar vasorelaxation effect of AngII in the chicken.