Twenty cases of malignant lymphomas (ML) of the oral cavity were reviewed in the light of recent histologic classification. They occurred in 12 male and 8 female patients, with the age range of 11-80 years (median 51 years of age). Eighty percent of patients were stages IE and IIE. Histologically, 15 cases (75%) were ordinary non-Hodgkin's lymphoma (NHL) with diffuse large cell type being the most common. The remaining 5 cases, undefinable by classification scheme for ordinary NHL, were designated as malignant histiocytosis of the oral cavity (3 cases) and peripheral T-cell lymphoma (2 cases), respectively. There were no cases of follicular lymphoma. The present cases comprised 45% of high grade, 40% of intermediate grade, and 15% of low grade malignancy. A follow-up study showed that the stage of diseage, histologic classification, and frequency of mitosis correlated well with survival.