Capecitabine is a fluoropyrimidine carbamate capable of exploiting the high concentrations of thymidine phosphorylase in tumor tissue to achieve activation preferentially at the tumor site. Thymidine phosphorylase activity is high in renal cell carcinoma tissue. Interferon alfa has been proved to be the agent for standard therapy in metastatic renal cell carcinoma. The purpose of the study was to assess the efficacy and toxicity of combining capecitabine and interferon alfa-2A in patients with advanced renal cell carcinoma. Twenty-five patients with advanced renal cell carcinoma and no prior systemic therapy were treated with the combination of capecitabine at a dose of 1,250 mg/m2 twice daily for 2 weeks after every 21 days and interferon alfa-2A 6 million U three times a week. The overall response rate was 24.0% (95% CI, 9.4-45.1%), from 6 responded patients 5 had partial responses and 1 complete response. Stable disease status was achieved in 9 patients (36.0% with 95% CI 18.0-57.5%). The median survival time was 248 days (95% CI, 173-265 days). The median time to progression was 126 days (95% CI, 49-165 days). Grade 3-4 toxicities occurred in 12 patients and included fatigue (33.3%), nausea, hand-foot syndrome (both 12.5%), anorexia (8.3%), vomiting, anemia and neutropenia (all 4.2%). The capecitabine and interferon alfa-2A combination has clinical activity and an acceptable toxicity profile in patients with metastatic renal cell carcinoma. The importance of adding capecitabine to interferon alfa needs to be confirmed in a randomized trial.