N-methylformamide (NMF) (800-1,000 mg/m2 i.v. day 1) was given to 14 patients with measurable, advanced renal cell carcinoma in this Phase II trial. Treatment was repeated every 28 days. Significant toxicities included drug-induced hepatitis along with moderate nausea and vomiting. No objective responses were seen although several patients had stable disease with treatment for prolonged periods. NMF is not an active agent in renal cell cancer when administered by this schedule.