The effect of the combination treatment consisted of 5'-deoxy-5-fluorouridine (5'-DFUR) and medroxyprogesterone acetate (MPA) was investigated in 20 recurrent breast cancer patients. Out of 20 patients, 8 (40.0%) responded to the treatment. The average duration of response was 10.3 months. Response rates stratified by recurrence site were soft tissues 36.4%, bone 44.4%, liver 60.0% and lung 20.0%, respectively. No serious side effect except body weight gain, which was caused by MPA, was seen. In a 76-year-old woman with liver metastases, a marked response was obtained and has continued for more than 24 months. It was suggested that the combination of 5'-DFUR and MPA may be effective for recurrent breast cancer patients.