Gastric cancer invading the subserosa with infiltrative growth was classified as part of the serosal invasion group and named prognostic serosal invasion positive [ps(+)] histologically. We analyzed clinicopathological features and prognosis of 166 Japanese patients with gastric cancer invading the subserosa, according to the growth pattern. All patients were treated in the Department of Surgery II, Kyushu University. Patients with infiltrative growth (ss gamma) were younger and their tumors were frequently undifferentiated compared to findings in those with noninfiltrative growth: expansive (ss alpha) and intermediate growth (ss beta). There was no difference in any other clinicopathological characteristic between those with infiltrative and noninfiltrative growth tumors. The 10-year survival rate was 66.7% for the infiltrative type and 54.2% for the noninfiltrative type, with no statistically significant difference. Lymph node metastasis, curative resection, and extended lymph node dissection, but not growth pattern, proved to be independent prognostic factors, as determined by multivariate analysis. Our findings suggest that it is not the growth pattern which affects the prognosis of ss cancers. Extensive lymph node dissection should be done when lymph node metastasis is present.