Oncocytoma is a neoplasm that constitutes 4-5% of tumors located in the renal parenchyma. It was studied for the first time by Zippel in 1942 and since than nearly 150 cases have been described. The association between neoplasm and horseshoe kidney is extremely rare. The horseshoe kidney is a malformation which often becomes complicated by infection, hydronephrosis and calculosis, but very rarely by a neoplasm (only 113 cases). The Authors report a case of oncocytoma in the horseshoe kidney and discuss the diagnostic, clinical and therapeutical aspects.