Asynchronous involvement of both testes by non-Hodgkin's lymphoma was observed in 3 patients ranging in age from 38 to 82 years. According to the Working Formulation, all cases were classified as large cell immunoblastic lymphomas, and immunohistochemical studies demonstrated a T-cell phenotype in 1 patient and a B-cell phenotype in 2 patients. Relapse to the contralateral testis occurred after a mean interval of 6 months. The negative prognostic impact of these neoplasms is confirmed in the present series, since 2 patients died of disease 7 and 9 months after diagnosis and 1 patient had a laterocervical and Waldeyer's ring recurrence after 1 year.