Six patients with conjunctival non-Hodgkin's lymphoma (NHL) were evaluated. In all six cases the conjunctiva was the primary site of clinical presentation; four cases involved low-grade malignancy and two, intermediate-grade malignancy, according to the International Working Formulation. The disease developed within a short period of time to stage IV. The poor response to therapy revealed a worse prognosis than would be expected according to the histopathologic classification. Four of the six patients died of NHL, three of them within 15 months. Comparison of these 6 cases with a group of 15 patients with orbital NHL revealed a much better prognosis in the latter patients. In spite of the fact that 4 of the 15 orbital cases showed NHL of high-grade malignancy, only 2 of them died of the lymphoma. Therefore, conjunctival NHL requires a fast and adequate diagnostic and therapeutic approach.