Patients with renal cell carcinoma (RCC) may exhibit renal impairment as a more or less direct consequence of their primary disease. Renal impairment may become a severe complication and alter the normal pharmacokinetic and pharmacodynamic behavior of treatment drugs, thus increasing the risk of side effects. We will discuss the cases of two advanced RCC patients with end-stage renal impairment submitted to dialysis who were treated with sorafenib tosylate in our center. Our experience confirms the scarce literature data available so far that indicate that sorafenib can be used in patients undergoing dialysis. Dialysis cannot be considered per se a contraindication to sorafenib therapy, which can be effective. However, patients must be carefully selected and monitored, since sorafenib administration unquestionably increases the risk of side effects in patients affected by several conditions.