Background and Objectives: The prognosis for patients with pN0 gastric cancer is moderately hopeful (expected 5-year survival: 80%). However, the relevant prognostic factors and most appropriate surveillance protocol have not been identified. Methods: We investigated 733 gastric cancer patients without lymph node metastasis for prognostic factors by uni-and multi-variate analysis and by documenting causes of death and recurrence patterns. Results: Univariate analysis revealed that age, tumor location, macroscopic appearance, tumor diameter, invasion depth, lymphatic invasion, and venous invasion affected prognosis. Multivariate analysis showed that age (!60 years), ill-defined macroscopic appearance, and undifferentiated histological type independently reduced survival rates. Age (!60 years) and undifferentiated histological type adversely influenced prognosis in 507 early gastric cancer patients whereas ill-defined macroscopic appearance adversely affected prognosis in 226 advanced cancer patients. Recurrence patterns in these patients were similar to those produced by lymph node metastasis. The predominant recurrence pattern was peritoneal dissemination, observed 2-3 years post-resection. Conclusions: This study identified adverse prognostic factors in pN0 gastric cancer patients. Randomized controlled studies of adjuvant chemotherapy are necessary to assess whether such therapy is beneficial for patients with adverse prognostic factors.