defined as the proportion of patients who either had a pathological complete response after surgery or sustained a clinical complete response for at least 1 year under surveillance. OBJECTIVE: To identify the predictors of complete response to total neoadjuvant therapy and compare different diagnostic tools in predicting complete response. DESIGN: Retrospective cohort study. SETTINGS: A single tertiary care center. PATIENTS: Patients with stage II and III rectal cancer who were diagnosed between January 2015 and December 2021. INTERVENTION: Total neoadjuvant therapy. MAIN OUTCOME MEASURES: Complete response rate, predictors of complete response, sensitivity and specificity of sigmoidoscopy, and MRI in predicting complete response. RESULTS: One hundred nineteen patients (mean age 56 [±11.3] years, 47 [39.5%] women, 100 [84%] stage III rectal cancer) were included. The median tumor size was 5.1 (4–6.5) cm, and 63 (52.9%) were low rectal tumors. Twenty-one patients (17.6%) had extramural