Purpose. The anal canal has a complex anatomy and histology and gives rise to various tumor types. Challenging issues remain in regard to both the pathologic diagnosis and the clinical management of these tumors. The aim of the retrospective study was to evaluate the clinical outcome in patients with anal cancer at a single institution. Methods. A retrospective data analysis was performed for patients with anal cancer treated in Taipei Medical University Hospital from 2008 to 2018. During this period, there were 23 patients diagnosed with anal cancer. Our analysis included data from hospital records, outpatient charts, and tumor registry data. Complete clinical responses, incomplete clinical responses, and recurrence were defined based on clinical, image and endoscopic findings. Results. There were 16 cases of anal squamous cell carcinoma, six cases of anal adenocarcinoma and only one case of well-differentiated neuroendocrine tumor. Follow-up information was available for 22 patients, with a mean follow-up period of 4.5 years (range, 1-10 years). To anal squamous cell carcinoma, the total complete response rate was 14/16 (87.5%), and the stage III cases complete response rate was 9/10 (90%). Three anal squamous cell carcinoma cases with complete response were recurrence. According to our data about all the anal squamous cell carcinoma cases, four patients with distant metastasis died after that. The 5- year survival rate of anal squamous cell carcinoma was 81.3%, and the 5- year survival rate of anal adenocarcinoma was 80%. There were six human Immunodeficiency virus anal squamous cell carcinoma patients with concurrent chemo-radiotherapy, and the complete response rate was 5/6 (83.3%). No obvious difference was found compared to non-human Immunodeficiency virus cases. Conclusions. To anal squamous cell carcinoma, 5-fluorouracil plus mitomycin C combined with radiotherapy leads to an outstanding clinical outcome, even in cases with human Immunodeficiency virus or stage III. Therefore, 5-fluorouracil plus mitomycin C chemotherapy combined with radiotherapy is the standard of care for all loco-regional anal cancer.