Interleukin-2 (IL-2) and alpha-interferon have each shown antitumor activity in patients with disseminated malignant melanoma. Because animal studies suggest enhanced activity for the combination over each agent used alone, this trial using a relatively low-dose outpatient regimen was undertaken. IL-2 at a dose of 2 x 10(6) U/m2/day (Roche units) was given by continuous intravenous infusion for 4 days a week with interferon-alpha-2a at a dose of 6 x 10(6) U/m2/day given by s.c. or i.m. injection on days 1 and 4 of each treatment week. One cycle consisted of 4 consecutive weeks of treatment followed by a 2-week rest period. Fourteen patients were entered in this study. No complete or partial responses were seen. One patient required dose reduction because of grade 3 diarrhea and two patients had interruption of treatment because of central-line-related sepsis. Fatigue was common in all patients. This low-dose combination regimen of IL-2 and alpha-interferon does not appear to be better than the single agents used alone in optimal dosage.