The amidation of polyaromatic carboxylic acids, such as 4-biphenylcarboxylic acid, 4- biphenylacetic acid, 4-carboxy-4′-hydroxybiphenyl, and N-phenylanthranilic acid, was satisfactorily carried out to give the corresponding amides using a wild-type bacterium, Bacillus cereus (w), in an aqueous medium.