Patients with metastatic renal cell carcinoma (RCC) generally show a poor prognosis; treatment approaches have not significantly improved patient survival. Temsirolimus inhibits the mammalian target of rapamycin kinase. Clinical studies have shown positive results when the drug is administered to patients with this disease. The clinical benefit of temsirolimus for poor-risk, advanced RCC patients was demonstrated in a Phase III study comparing temsirolimus with interferon alpha (IFN-alpha) or combined temsirolimus plus IFN-alpha as first-line treatment of advanced RCC, showed that treatment with temsirolimus alone significantly increased median overall survival in poor-risk, advanced RCC patients (10.9 vs 7.3 vs 8.4 months). This was the first Phase III trial to demonstrate an overall improvement in survival using an agent as "targeted therapy" for patients with advanced RCC. By November 2007, 200 patients with advanced RCC had been treated with temsirolimus before its approval by the European Medicines Agency (EMEA) within a compassionate use program. The single-center treatment experiences using temsirolimus in patients for compassionate use are described herein. The treatment was generally well tolerated; side effects (mucositis, diabetes, and peripheral edema) were within the range expected from the pivotal trials and manageable with supportive care. Further development strategies for temsirolimus in patients with RCC include its evaluation with bevacizumab and also as second-line therapy in patients who have failed first-line therapy with sunitinib.