Three hybridomas producing monoclonal antibodies to angiotensin II were generated using somatic cell fusion techniques. Dissociation constants, determined by Scatchard analysis of radioimmunoassay data, were 9.3 X 10(-10) M, 1.5 X 10(-9) M and 1.8 X 10(-8) M for antibodies KAA8, ICH2 and ICA10, respectively. The antibodies exhibited various degrees of cross-reactivity towards peptide metabolites of angiotensin II, but minimal cross-reactivity towards antagonists created by substituting the hormone at both the amino and carboxy terminus. In contrast to a rabbit polyclonal angiotensin II antibody preparation, the three monoclonal antibodies competed effectively with angiotensin receptors on rat adrenal cortical microsomes for hormone binding. These antibodies may have broad utility for a number of applications in angiotensin II research.