Background: To report our initial experiences using a combined retroperitoneoscopic and transperitoneal laparoscopic technique for the management of renal cell carcinoma with level I tumor thrombi. Materials and Methods: Two patients underwent this technique for tumors 11- and 13-cm in diameter. After transection of the renal artery with limited mobilization of the kidney using a retroperitoneoscopic approach, additional ports were placed, and the management of the tumor thrombus was performed in the large working space provided by the transperitoneoscopic approach. Results: The technique was feasible in the present 2 cases. The total operative times were 170 and 200 min, respectively. The estimated blood loss was 450 cc in the first case and 200 cc in the second case. No complications were observed in either of the patients. Conclusions: Based on the initial clinical experience, we have presented a feasible surgical option for the laparoscopic management of renal cell carcinoma with level I thrombi.