Fourteen patients with well- or intermediately differentiated monoclonal B-lymphocytic tumors of the conjunctiva or orbit had a favorable prognosis with follow-ups of 4 to 9 years (mean and median, 7.5 years). The lesions were, for the most part, diffuse proliferations of small lymphocytes, either with round or minimally indented nuclear outlines. Mitotic activity was sparse to nonexistent; occasionally there were scattered small abortive or residual germinal centers, and some lesions exhibited lymphoplasmacytoid features and dispersed multinucleated giant cells (polykaryocytes). None of the six patients with conjunctival lesions had extraocular manifestations. An identical tumor of the submandibular gland developed in one of eight patients with orbital lesions and another patient had multiple extranodal involvements of the oropharynx, liver, and both kidneys, but after chemotherapy the patient has survived for 8 years from orbital presentation and is currently in remission. The authors believe that these low-grade tumors share many biologic resemblances to extranodal lymphoepithelial tumors of other organs (lung, gut, parotid, thyroid), which as a group have been aggregated together as mucosa-associated lymphoid tumors (MALT) and which can often remain localized to their sites of origin.