Despite recent advances in the systemic chemotherapy of patients with malignant trophoblastic disease, there remains a small group of patients who fail to achieve remission with this type of treatment. The present study presents 19 patients with malignant trophoblastic disease who underwent a total of 25 arteriographic studies for localization of persistent malignant lesions and 8 patients who underwent arterial infusional chemotherapy after they had failed to achieve remission by standard administration of systemic methotrexate or actinomycin D. Patients underwent pelvic, pulmonary, carotid, and multiple abdominal selective arteriograms with a high correlation of positive findings and the later documented presence of persistent malignant disease. Findings included prominent uterine arteries, arteriovenous shunts, hypervascularity, irregular vessels, and tumor staining within the tumor. Arterially infused chemotherapy with methotrexate or actinomycin D was used in 8 patients whose disease was resistant to systemic chemotherapy. Technics of arterial infusion are discussed.