Recent interest in nephron sparing surgery for renal cell carcinoma has been stimulated by advances in diagnostic imaging, following an increasing number of incidentally discovered low stage renal cell carcinoma and good long term survival in patients undergoing this form of treatment. Tosaka et al reported a 5-years survival of 94.7% in patients with incidental renal cell carcinoma compared with 60.9% in diagnosed because symptomatic. Along with a diagnosis of carcinoma more and more premature, a whole string of little lesions is present, not easily identifiable by the recent diagnostic imaging. Tosaka and others examined renal lesions going by the ultrasonography as a check-up or as a first frame in patients suffering from microscopic hematuria; they proved that neoplastic lesions represent 5.4% of all the masses identifiable by diagnostic imaging. The frequent discovery of limited carcinoma, the difficulty in the diagnostic attribution and demonstration of the good survival of patients who were treated by a nephron sparing surgery, added to the one of patients undergone to radical nephrectomy, caused an interest in nephron-sparing surgery for incidental renal carcinoma also for patients with normal controlateral kidney and not very extended tumors, usually in peripheral sites. At the moment record of cases concerning nephron sparing surgery is quite limited, any way it shows a survival equal to 90% with only two local recurrences, reported only in one experience and caused by an incomplete resection or by multicentric neoplastic lesions.