Between the years 1973-1977, 152 male patients from 28 participating Veterans Hospitals with histologically proven nonresectable cancer of the pancreas were randomized in a two-arm study. The treated group was to receive combination chemotherapy with 5-FU and CCNU, and the controls were to receive no chemotherapy. Both groups were comparable with respect to age, amount of weight loss, extent of histologically proved metastases, and operation performed. In the treatment group, drug therapy was begun between 10 and 60 days postoperatively. Intravenous 5-FU, 9 mg/kg, was administered on five consecutive days, and CCNU, 70 mg/m2, was given orally on the first day of each course. In the absence of toxicity, the course was repeated every six weeks for life; 146 drug courses were given. The incidence of toxicity was not great. One or more toxic reactions were reported for one-third of the drug courses administered, but for the most part, these were mild. The most frequent toxic reaction was vomiting in 17% of the courses, and hematologic toxicity-primarily leukopenia-in 15% of the drug courses. There was no evidence of a beneficial effect on survival from drug treatment in the group as a whole or in any subgroup analyzed. The median survival of the control group was 3.9 months, and of the drug-treated group, 3.0 months.