Background: Literature pertaining to prophylactic inguinal nodal treatment for anal adenocarcinoma in China is scarce. Methods: In this retrospective study, we analyzed 126 patients from 1965 to 2015. Among these, 67 patients received surgery only, 18 patients received chemoradiotherapy only, 27 patients received a combination of both, and the remaining 14 patients received palliative treatment. Results: The median follow up period was 30 months. The 1-year, 3-year, and 5-year overall survival rates were 85.8%, 62.5%, and 43.4%, respectively. The 5-year overall survival was 46.9% for patients with negative inguinal lymph nodes and 19.1% for patients with positive inguinal lymph nodes (p=0.007). The overall 5-year inguinal node relapse-free survival was 83.0%. The 5-year inguinal node relapse-free survival was 87.5% for stage I, 86.9% for stage II, and 76.5% for stage III cancers. Among those with negative inguinal nodes, the 5-year inguinal node relapse-free survival was 85.7% for negative regional lymph nodes and 75.4% for positive regional lymph nodes (p=0.089). Conclusion: Inguinal lymph node is a high-risk subclinical area. Prophylactic inguinal nodal treatment is necessary for patients with anal adenocarcinoma irrespective of positive or negative inguinal lymph nodes.