Recently, the primary structure of the cholecystokinin A-type (CCK-A) receptor has been determined. From the Kyte-Doolittle-predicted hydrophobic stretches of this sequence and the transmembrane domains of bacteriorhodopsin, a membrane-bound protein of known tertiary structure, a three-dimensional model of the membrane-embedded part of this receptor was built. Subsequently, the modelled receptor pore was searched for a binding site that matches the structural and conformational characteristics of the parent classes of the antagonists devazepide and lorglumide. In addition, the binding mode of hybrid analogues of these reference compounds was examined. The proposed antagonist, binding site includes regions in which hydrophobic, hydrogen-bonding and aromatic interactions stabilize the receptor-ligand complex.