Bilateral renal cell carcinoma is detected at an incidence rate of 1.6-6% of all renal tumors. The management, histopathological results and the long-term follow-up of 66 patients with bilateral renal cell carcinoma (29 synchronous, 37 asynchronous tumors) are presented in this issue. The incidence rate of bilateral renal cell carcinoma (RCC) at our hospital was 3.5%. Nephron-sparing surgery should be used first for the smaller and favourably located tumor when radical nephrectomy of the contralateral tumor is necessary. Thus, the patients can be spared dialysis. The histopathological results showed a significantly higher incidence rate of chromophil RCCs in cases of synchronous bilateral renal tumors (36%). The 5-year survival rate was 82%. Patients with asynchronous renal cell carcinomas were significantly younger than those with synchronous RCCs (median age: 60.2 years). The histopathological results were similar to unilateral renal cell carcinomas. Clear cell carcinoma was detected in 70% of cases. The 5-year survival rate was 61% and lower than that of synchronous tumors (82%). There was no significant difference because of the small number of cases. Current standardised techniques of nephron-sparing surgery achieve good survival rates, therefore making bilateral nephrectomy only necessary in very poor cases. In cases of chromophil renal cell carcinomas, the contralateral kidney should always be carefully examined, because these tumors were significantly more often detected to be bilateral. The risk of also developing a tumor in the contralateral kidney increases with decreasing age at first manifestation (< 55 years, 6%). Especially in those younger than 55 years, partial nephrectomy seems to be recommended for unilateral renal tumors in patients with a normal contralateral kidney (tumor size < 4 cm in diameter).