The usefulness of MR imaging (MRI) in uterine cervical cancer after radiotherapy was evaluated in 18 patients. MRI was performed before and within one month after radiotherapy. In eight patients the uterus assumed a nearly normal appearance with resolution of the tumor on MRI. In another eight patients the tumors resolved, but an area of high signal intensity remained at the cervix. In these patients the tumors were well controlled at clinical examinations and during the mean follow-up period of 15-18 months. Therefore a persistent area of high signal intensity alone at the cervix on MRI is not itself indicative of residual tumor. An area of high signal intensity and a residual cervical mass persisted in two cases, and they were histologically proven to be due to residual tumor. Both patients died of recurrent disease at seven and 11 months after their radiotherapy. We conclude that MRI is useful for evaluating patients with cervical cancer at the completion of radiotherapy, and that MRI complements conventional clinical examinations.