A 77-year-old female with primary duodenal cancer had undergone pancreatoduodenectomy in May, 1989. Postoperative chemotherapy was done in combination with MMC (mitomycin C), lentinan and UFT (combined medicine of tegafur and uracil). In August, 1991, the patient complained of a cough and then was examined for multiple pulmonary metastases from duodenal cancer by chest X-ray and CT-scan. Then, she received 5'-DFUR (400-800 mg) and MMC (total 6 mg). Two months from the start of this therapy, the cough almost vanished and pulmonary lesions were diminished markedly. For about five months, this case corresponded to partial response (PR) according to the response criteria proposed by Koyama-Saitoh. The side effects of 5'-DFUR were diarrhea and anorexia. Therefore, we think that 5'-DFUR and a small dose of MMC yielded a partial response to multiple pulmonary metastases from duodenal cancer.