Primitive neuroectodermal tumor (PNET) of the kidney is rare. Mostly patients with renal PNET are young adults and the survival rates are poor. Although radiological and pathological investigations, differential diagnosis from other kidney tumours is very difficult. The treatment is often delayed because of difficulties with diagnosis. In most cases of renal PNET, as in this case, prognosis is poor. Particularly, in young adults with large renal masses, it must be diagnosed and treatment should be started immediately.