Renal cell carcinoma is the most lethal amongst urological malignancies. Only surgical excision of the tumor offers the chance of curative therapy for patients with localized disease. Nephron-sparing surgery is mandatory for patients with renal tumors in both kidneys or in a solitary kidney in order to preserve renal function (imperative indication). Evaluation of patients with renal tumors in both kidneys or in a solitary kidney must weigh the surgical and oncological risks of nephron-sparing surgery against the morbidity of radical nephrectomy followed by hemodialysis and possibly renal transplantation. Herein we report our oncological and functional long-term results of nephron-sparing surgery in patients with an imperative indication and review the literature.