Purpose: We evaluated the clinicopathological charicterics and prognostic impacts of lymphatic vessel invasion in gastric cancer without lymph node involvement. Materials and Methods: Among 1,795 patients who underwent gastric surgery with gastric cancer at the department of surgery, Hanyang university college of medicine from June 1992 to March 2009, we retrospectively evaluated 890 patients with lymph node negative gastric cancer. Results: The lymphatic vessel invasion correlated significantly with tumor stage, age, tumor size, perineural invasion and operation method. The survival rates were only significantly different between the patients with and without lymphatic vessel invasion in patients with stage Ia (P=0.036). Univariate and multivariate analysis demonstrated that blood vessel invasion and preoperative serum CEA level were significant factor influencing the survival rate in lymph node negative gastric cancer patients with lymphatic invasion. Conclusions: In patients with lymph node negative gastric cancer, the survival rate is significantly lower in those with lymphatic vessel invasion than in those without. Especially, in patients with stage Ia gastric cancer, the survival rates is significantly different between those with and those without lymphatic vessel invasion. Blood vessel invasion and preoperative serum CEA level is an adverse prognostic indicator in patients with stage Ia gastric cancer with lymphatic invasion. Thus we should consider further adjuvant therapies in case of need and need to show more concern to identify gastric cancer patients early at risk for recurrence.