OBJECTIVE The purpose of this study was to evaluate the efficacy of en bloc nephrectomy for perirenal retroperitoneal sarcoma (RPS) with respect to postoperative kidney function and oncological benefits. METHODS We performed a comparative study of 114 patients undergoing surgery for primary RPS, classifying cases as nephrectomy (NPX, n = 65) versus no nephrectomy (no-NPX, n = 49). The Δ and % change between preoperative and postoperative estimated glomerulus filtration rate (eGFR) were analyzed to compare renal function changes after surgery. Kaplan-Meier analysis was performed to verify the incidence of local relapse between the two groups. RESULTS During a median follow-up of 29 months, median postoperative GFR of 65 patients in the NPX group decreased to 73.5% of preoperative eGFR. Although 38 patients (58%) in the NPX group experienced a progression in chronic kidney disease stage after nephrectomy, no patients progressed to end-stage renal disease (ESRD). In French Federation of Cancer Centers Sarcoma grade 2, the NPX group had statistically significant local control benefits, compared with the no-NPX group (P = 0.048). CONCLUSIONS Residual renal function after en bloc nephrectomy was stabilized without progression to ESRD. Moreover, en bloc nephrectomy for perirenal RPS might secure a complete resection margin for local tumor control.