The study group comprised 10 patients who were referred between 1992 and 1996 with non-Hodgkin's lymphoma arising in the thyroid gland. There were three men and seven women, with a median age of 75 years, and seven of the group had a history of Hashimoto's disease. All 10 patients had hypothyroidism; anti-microsomal antibody was positive in six. The lymphoma was of the diffuse type in all patients (B cell, 9; T cell, 1). Five patients had stage I and five had stage II. Generally, four courses of COP-BLAM therapy were given, followed by radiotherapy (30 Gy). Complete remission was achieved in all patients, and they remained alive and disease-free for a median period of 40 months. Ultrasonography revealed diffuse, an-or hypoechoic confluent nodules, and there was intensification of the posterior acoustic enhancement in most patients. With early diagnosis non-Hodgkin's lymphoma arising in the thyroid of elderly patients, mainly women, can be cured with chemotherapy and radiotherapy.