Eighty-five patients, median age 55 years, with evolutive metastatic carcinoma of unknown primary (CUP) were included in this study. The treatment combination consisted of fluorouracil (5-FU) (600 mg/m2 in a 30 min infusion) days 1 and 8, doxorubicin (DXR) (30 mg/m2 by i.v. bolus injection) day 1 and cisplatin (CDDP) (80 mg/m2 in a 4-h infusion) day 1. Altretamine (HMM) (150 mg/m2) was administered orally days 2-8, therapy being resumed every 29 days. An objective response was noted in 18/85 patients (21%) with a median duration of response of 7 months. Thirty-three/77 patients (43%) who had tumor-related symptoms were relieved of their troubles. The overall median survival of patients was 7 months; the median survival of responders was 12.5 months. Toxicity occurred in one-third of patients (mainly digestive and hematologic), leading twice to a halt in treatment and to drug dose reduction in 26/77 (33%) evaluable patients. Such a regimen is of limited efficacy, has a non-negligible toxicity and appears of little interest in such a palliative situation.