Gemcitabine is a fluorine-substituted cytarabine analog with broad experimental antitumor activity. It's activity was explored in chemotherapy-naive patients with advanced progressive renal-cell carcinoma. A total of 39 patients were included in the study, of whom 37 were fully evaluable. In five patients the primary tumor remained in situ. Gemcitabine at 800 mg/m2 was given as a weekly 30-min infusion for 3 consecutive weeks followed by 1 week of rest. One complete response and two partial responses were observed giving a response rate of 8.1% [95% confidence interval (CI), 2-22%]. The duration of the responses is currently 32, 15, and 19 months, respectively. The median survival for all patients was 12.3 months. Gemacitabine was generally well tolerated, with nausea and vomiting (20.5% grade III) and neutropenia (5.3% grade III) being the most significant side effects. Gemcitabine given at this dose level and on this schedule has only limited activity in advanced renal-cell carcinoma.