An inducible rabbit endothelial adhesion molecule that is selective for mononuclear leukocytes has been identified. This adhesion protein was expressed on the surface of activated cultured endothelium in two forms, 118 and 98 kilodaltons, the amino-terminal sequence of each being highly homologous to human VCAM-1. In dietary hypercholesterolemic and Watanabe heritable hyperlipidemic rabbit models of atherosclerosis, this adhesion molecule was found to be expressed in a localized fashion by aortic endothelium that overlies early foam cell lesions. This lesion-localized expression suggests a potential endothelium-dependent mechanism for mononuclear leukocyte recruitment during atherogenesis and may provide a molecular marker for early atherosclerosis.