Primary testicular lymphoma is an uncommon testicular tumour. We present a case of a primary non-Hodgkin lymphoma of the testis, describing its clinical and pathological features and discussing our treatment strategy. A 68-year-old man showed a firm erythematous testicular mass within the right emiscrotum. Subsequent ultrasonography demonstrated a right inferior pole testicular mass with disomogenously hypoecogenic. The patient was submitted to inguinal orchidectomy. Light microscopy demonstrated the classic appearance of a diffuse large B-cell lymphoma. The immunohistochemical study showed tumour cells intensively positive for CD45, Ki67 and CD20. No evidence of extra-testicular involvement by lymphoma was found. At 6 months, a TC-PET showed a clinical relapse in lung and abdominal lymphonodes, while clinical examination demonstrated a single, indolent and erythematous nodule in the left foot. The histologic analysis confirmed diagnosis of CD-20 positive B-cell lymphoma. The patient was treated with an anti-CD 20 monoclonal antibody (rituximab) alone every 3 weeks. After 3 months a complete response was observed in all sites of disease. The patient was free from disease at 12 months follow-up.