A case of human fetal renal maldevelopment following the administration of nitrogen mustard, vincristine, procarbazine, and prednisone in early pregnancy for therapy of Hodgkin's disease is reported. While these agents have been shown to be teratogenic in animal experiments, adverse fetal effects following their use during early human pregnancy have not been described. In spile of this previous experience, it has generally been recommended that these agents be withheld during the first trimester of pregnancy because of their presumed teratogenic potential. This case would seem to reinforce this recommendation.