PURPOSE: To evaluate the predictive factors for treatment response and prognostic factors affecting survival outcomes after concurrent chemoradiotherapy (CCRT) for patients with anal squamous cell carcinoma. MATERIALS AND METHODS: Medical records of forty two patients with histologically confirmed analsquamous cell carcinoma, who had complete CCRT between 1993 and 2008, were reviewed retrospectively. Median age was 61.5 years (39~89 years), and median radiotherapy (RT) dose was 50.4 Gy (30.0~64.0 Gy). A total of 36 patients had equal to or less than T2 stage (85.7%). Fourteen patients (33.3%) showed regional nodal metastasis, 36 patients (85.7%) were treated with 5-fluorouracil (5-FU) plus mitomycin, and the remaining patients were treated by 5-FU plus cisplatinum. RESULTS: The median follow-up time was 62 months (2~202 months).The 5-year overall survival, locoregional relapse-free survival, disease-free survival, and colostomy-free survival rates were 86.0%, 71.7%, 71.7%, 78.2%, respectively. Regarding overall survival, the Eastern Cooperative Oncology Group (ECOG) performance status and complete response were found to be significant prognostic factors on univariate analysis. For multivariate analysis, only the ECOG performance status was significant. No significant factor was found for locoregional relapse-free survival or disease-free survival and similarly for treatment response, no significant factor was determined on logistic regression analysis. There were 7 patients who had local or regional recurrences and one patient with distant metastasis. The only evaluable toxicity in all patients was radiation dermatitis of perianal skin (grade 3), which developed in 4 patients (9.5%) and grade 2 in 22 patients (52.4%). CONCLUSION: This study revealed that patients with a performance score of ECOG 0-1 survived significantly longer than those with a poorer score. Finally, there was no significant predicting factors tested for treatment response.