OBJECTIVE Maintaining adequate renal function without compromising cure in children with bilateral Wilms' tumor is surgically demanding and challenging. The aim of this study was to assess renal function and outcome in children treated in one institution for bilateral Wilms' disease by renal salvage procedures. METHODS This study is a retrospective review of all patients with histologically proven bilateral nephroblastoma who underwent a renal salvage procedure between November 1973 and June 2002. The median follow-up time was 52 months (range, 8 to 326 months). RESULTS Twenty-three patients were included in the study. The median age at diagnosis was 19 months (range, 5 to 65 months). Patients who presented before 1982 (n = 5) were treated surgically first followed by chemotherapy. The remainder (n = 18) received initial chemotherapy before the operation. Of the 46 kidneys, 18 had a nephrectomy. The remaining 28 underwent a renal salvage procedure. At follow-up, 19 patients had good renal function, 2 had satisfactory function, and 2 had renal failure. Seventeen of the 23 children are alive and tumor free at follow-up (74%). Four children died of distant metastases and 2 of renal failure. Local recurrence in the salvaged kidney was detected in 1 patient 12 years after surgery after the commencement of immunosuppression for renal transplantation. CONCLUSIONS These results confirm that renal salvage procedures, in combination with chemotherapy, are a safe and effective way of treating children with bilateral Wilms' disease. In addition, renal salvage surgery can maintain satisfactory renal function in the majority of these patients without an increased risk of local recurrence. When transplantation is required, the remaining native kidney should be removed to prevent tumor recurrence.