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 HE. 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 s