By using SP immunohistochemical methods, the correlation of the expression of P53 and nm23 with the biologic behavior and lymph node metastasis in gastric carcinomas was studied. Abnormalities of P53 expression were found in 49% of the 88 primary gastric carcinomas. A significant correlation was found between P53 overexpression and the depth of invasion and the proliferative activities (Pearson Contingency Coefficient P = 0.32 and 0.35, P < 0.05, respectively). The metastatic rate of tumours stained positively for P53 (93%) were higher than in those with negative P53 staining (60%, P < 0.05). Meanwhile, a significant correlation of low expression of nm23 with the depth of cancer invasion was found (Pearson Contingency Coefficient P = 0.28, P < 0.05). nm23 low-expressive tumours were associated with a higher incidence of metastasis to lymph nodes (93%) than were nm23-normal expressive (49%, P < 0.05). The contributions of P53 overexpression and nm23 low-expression to the lymph nodal metastasis were the independent joint action. It is suggested that P53 overexpression and nm23 low-expression might play significant role in lymph node metastasis and invasion and proliferation in the primary gastric carcinomas.