A series of phenoxyacetanilide derivatives was synthesized and their antagonist activities for human gastrin/cholecystokinin (CCK)-B and CCK-A receptors were evaluated. Among the compounds synthesized, 2-[3-[3-[N-[2-(N-methyl-N-phenylcarbamoylmethoxy) phenyl]-N-(N- methyl-N-phenylcarbamoylmethyl) carbamoylmethyl]-ureido] phenyl] acetic acid (20i, DA- 3934) exhibited high affinity for gastrin/CCK-B receptors and high selectivity over CCK-A ...