This paper describes the results of radiotherapy in early stage orbital non-Hodgkin's lymphoma. From 1970 to 1985, 33 orbital localizations in 30 patients were treated. The total dose applied ranged from 21 to 57 Gy (2 Gy per fraction), two-thirds of all patients received a dose of 40 Gy. The complete-response rate was 94% and the 10 years actuarial survival was 90%; no significant difference in survival was observed between patients with low grade or intermediate grade lymphoma. No local recurrence was detected during follow up and 20% of the patients developed generalized disease. Two optic nerve neuropathies and three retinopathies were observed in five patients, four of these occurred at a dose level of less than 43 Gy. Keratitis occurred in 58% of the patients treated, a sicca syndrome in 30% and cataract of different grades in 58% of the patients treated. Although local control was excellent, severe complications were observed in 13% of the patients who received a dose of less than 43 Gy.