After removal of a complete hydatidiform mole, seven patients developed an unusual complication characterized by a proliferation of intermediate trophoblast-forming nodules in the endometrium or myometrium. The patients were examined because of vaginal bleeding or mildly elevated human chorionic gonadotrophin (HCG) titers. Three patients were cured by hysterectomy, one by endometrial curettage, one by endometrial curettage plus chemotherapy, and one (who also had choriocarcinoma) by multiple doses of chemotherapy after hysterectomy; the seventh patient was lost to follow-up. These nodules probably represent a mild form of postmolar trophoblastic disease.