We present 17 cases of non-Hodgkin's lymphoma of the mandible, collected over a span of 10 years. Clinically, the patients showed a male:female ratio of 1:2.4 and a mean age of 60.6 years. Swelling was the most common symptom. In 11 of 17 patients, the disease presented in stage I. Radiotherapy alone was employed in 11 patients, in conjunction with chemotherapy in 5 patients, and was preceded by surgery in the remaining case. At this writing ten of the subjects are still alive, five died following progression of the disease, and two were lost during follow-up while in complete remission. Histopathology revealed 15 B-cell lymphomas (1 centroblastic/centrocytic, nine centroblastic, one Burkitt's, two immunoblastic, and two lymphoblastic) and two peripheral T-cell lymphomas (pleomorphic). The above diagnoses were confirmed by immunohistochemical analysis with a wide panel of reagents against fixative-resistant molecules. Our data suggest that (a) lymphomas of the mandible are principally represented by high-grade B-cell varieties (88%); (b) primitive T-cell lymphomas (here documented for the first time) have the same incidence in the mandible as they have in lymph nodes; and (c) immunohistochemistry, besides confirming histogenetic interpretations based on morphologic findings, provides the key to the differential diagnosis from malignant large-cell nonlymphoid tumors.