A series of competitive, nonpeptide bradykinin receptor antagonists based on an α-amino acid scaffold have been developed and biologically characterized. The lead compound in the series, WIN 64338, demonstrates competitive inhibition of bradykinin-mediated functional responses through B2 receptors in a variety of tissues and species. WIN 64338 is specific for the bradykinin B2 receptor; it is inactive at both the B1 and B3 kinin receptors. In conscious guinea pigs, WIN 64338 inhibits kinin-mediated bronchoconstriction but does not attenuate a similar response to acetylcholine. A series of WIN 64338 analogues display a well-defined structure-activity relationship, strongly suggesting binding in a specific manner to the B2 receptor. Structure-activity data suggest that a hydrophobic binding pocket that prefers large aromatic groups in a specific conformational orientation exists in the receptor ligand binding domain. This class of nonpeptide bradykinin receptor antagonists may lead to the design of other compounds with enhanced receptor affinity and optimal in vivo biological activity.