Over an 8-year period in the Departments of Hematology, Ophthalmology and Internal Medicine of our hospital, 12 cases of orbital and adnexal malignant non-Hodgkin's lymphoma were reported. Diagnostic elements varied, including local tumefaction, watering eyes, uveitis, and unexplained, long-term fever. Nine patients had primary paraocular lymphomas involving either orbital structures, the lacrimal gland or the eyeball, but after appropriate staging, the disease was found to be disseminated in 5; the 3 other cases were secondary orbital lymphomas. Intermediate or high grade histological types were predominant (9 patients) in our series. Radiation therapy, alone or combined (5 patients) with chemotherapy, was administered in 8 cases; other treatments consisted of chemotherapy (2 cases) or steroids (2 cases). Evolution was poor, with only 4 patients surviving at 34-180 months of follow-up. The main prognostic factors were tumor stage and histological grade. The clinical characteristics of this group are compared to those reported in the literature.