Aim: To explore the risk factors and prognosis for lymphatic metastasis (LNM) in patients with Siewert II/III adenocarcinoma of the gastroesophageal junction (AEG). Patients and Methods: This study retrospectively reviewed 49 patients with Siewert II/III AEG. Clinical characteristics and pathological features were analyzed by the Chi-square the and binary logistic regression. Survival data were analyzed using the Kaplan-Meier method. Results: LNM frequency was found in lymph nodes No. 1, No. 2, No. 3, No. 7, No. 11 and No. 110. The results revealed that depth of infiltration, neoplasms by histological type and lymphatic embolus were independent risk factors for LNM. The 1- and 3-year survival of patients without LNM were both 100%, while patients with LNM had 70% and 60% survival, respectively. Although the differences were not statistically significant, survival rate with negative lymph nodes was higher than in patients with LNM. Conclusion: Total gastrectomy combined with D2 No. 110 lymphadenectomy might improve the prognosis for LNM patients.