Proliferating cell nuclear antigen (PCNA) in gastric cancer was evaluated in relation to lymph node metastasis. A total of 125 gastric cancer patients who underwent gastrectomy were studied immunohistochemically. The PCNA-positive rate of the primary lesion with lymph node metastasis (47.6%) was significantly higher than those in those without metastasis (24.3%, P < 0.0001). The PCNA-positive rate of early gastric cancer was significantly higher in lesions with lymph node metastasis (36.9%) than in lesions without lymph node metastasis (14.7%). However, there was no significant difference between lesions with and without lymph node metastasis in advanced gastric cancer. In addition, the PCNA-positive rate in metastatic lesions (44.6%) was significantly higher than that in the primary lesion (40.0%, P = 0.001). It is concluded that gastric cancer with higher tumor growth activity has a higher rate of lymph node metastasis. Cancer cells in the metastatic foci of lymph node have a higher proliferating activity than that in the primary lesion.