The present report concerns a retrospective study of 16 patients with localized intermediate- or high-grade non-Hodgkin's lymphoma of the testis treated in one institution from 1973 to 1990. Ann Arbor stage of disease was IE in 11 and IIE in 5 cases. All except one patient underwent initial inguinal orchidectomy, 11 were disease free after surgery and 12 received inverted Y radiation therapy. All patients achieved a complete remission (CR). Relapse occurred in 8 of 9 patients who did not receive initial chemotherapy, but in only 3 of 7 patients initially treated with chemotherapy including anthracyclins. In 3 cases relapse was confined to the CNS, while diffuse relapse in 8 others included 4 cases of CNS involvement. Eight patients are now alive in CR (5 in first CR, 1 in second CR and 2 in third CR) with a median follow-up of 68.5 months (range 54-101). Chemotherapy thus emerges as the initial treatment of preference for localized testicular lymphoma. Therapy should be preceded by a thorough assessment of the stage of disease and due to the high frequency of CNS relapse, CNS prophylaxis should be considered for all patients.