The purpose of the study was to analyze surgical treatment outcomes for renal cell carcinoma (RCC) with inferior vena cava tumor thrombosis (IVC-TT) on the basis of one cancer center.Material and Methods. A retrospective analysis of treatment outcomes of 25 patients with locally advanced and metastatic RCC with IVC-TT, who underwent surgery from 01.2021 to 12.2022, was carried out. The median follow-up was 21 months (95 % CI 14.3–33 months). The patients were divided into groups according to the Mayo IVC-TT classifcation: Type I: 8 patients, type II: 8 patients, and type III: 9 patients.Results. Tangential IVC resection was done in 20 (80 %) cases, circular-in 3 (12 %) cases, and IVC extirpation was done in 2 (8 %) cases. The median intraoperative blood loss was 600 ml (from 250 to 1700 ml). The incidence of postoperative complications was 28 %, distribution by Clavien–Dindo classes was: III – 4, IV – 2, V – 1, an increase in the incidence of complications of class III–IV was revealed in patients with Mayo type III, however, no statistically signifcant differences were found (p=0.153). The most common complication was acute kidney injury. Two (8 %) patients required repeated surgical intervention. One patient died due to sepsis. Statistically signifcant differences were obtained in blood loss (p=0.003), the number of erythrocyte suspension blood transfusions (p=0.006), and the time of surgery (p=0.014) and prevailed in the group with the Mayo III level. However, the median length of hospital stay did not differ in the subgroups (p=0.978) and amounted to 6 bed days in the range from 4 to 20 days in the general group. The 30-day postoperative mortality rate was 4 %.Conclusion. Our experience has shown that surgical treatment of RCC with IVC-TT is feasible and provides acceptable surgical and oncological outcomes. However, the complication rate and postoperative mortality are higher in patients with Mayo III thrombus levels, requiring careful patient selection.