A series of 2-phenylbenzofuran derivatives with a diphenylmethylcarbamoyl group at the 5 or 6 position of the benzofuran ring were synthesized and evaluated for rat and human testosterone 5 alpha-reductase inhibitory activities in vitro. They had inhibitory activities against both enzymes and the 6-carbamoyl derivatives tended to be more potent than the 5-carbamoyl compounds.