In this study the authors detected both nm23-H1 and nm23-H2 mRNA levels in 52 tissues samples of patients with carcinoma of buccal mucosa (CBM) by Northern blotting method. The expression levels of both nm23-H1 and nm23-H2 mRNA in CBM were higher than those in normal buccal mucosa, leukoplakia, adjacent nontumorous mucosa, and lymph nodes with or without metastasis. The nm23-H1 mRNA expression levels in CBM with lymph nodes metastases were lower than those in CBM without metastasis, and were lower in metastatic lympho nodes (P < 0.05). Of the 11 cases with metastases, 9 cases (81.8%) showed low expression of nm23-H1 mRNA, of 19 cases without metastasis, 15 cases (78.9%) were high expression. No significance of nm23-H2 mRNA expression levels were found between CBM with and CBM without metastasis (P > 0.05). The expression of nm23-H1 and nm23-H2 mRNA showed no significant correlation with each clinical-pathological parameter examed. The result suggested that the expression of nm23-H1 mRNA significantly correlated inversely with lymph node metastasis in CBM, while the expression of nm23-H2 mRNA not. nm23 mRNA expression levels can provide a valuable predictor of lymph node metastases in CBM.