We present a case of necrotizing vasculitis with the testicle as the isolated affected organ. A 25-year-old man, pretreated for epididymo-orchitis, presented with a presumed testicular neoplasm. Radical orchiectomy was performed and diagnosis of necrotizing vasculitis was established. In the absence of any other sign of systemic disease, the diagnosis of isolated necrotizing vasculitis of the testis was confirmed. Two years after the operation, the patient showed no symptoms of systemic disease.