BACKGROUND/AIMS: Obesity is a much-debated factor with conflicting evidence regarding its association with cecum intubation rates during colonoscopy. We aimed to identify the association between cecal intubation (CI) time and obesity by eliminating confounding factors. METHODS: A retrospective chart review of subjects undergoing outpatient colonoscopy was conducted. The population was categorized by sex and obesity (body mass index [BMI, kg/m2]: I, <24.9; II, 25 to 29.9; III, ≥30). CI time was used as a marker for a difficult colonoscopy. Mean CI times (MCT) were compared for statistical significance using analysis of variance tests. RESULTS: A total of 926 subjects were included. Overall MCT was 15.7±7.9 minutes, and it was 15.9±7.9 and 15.5±7.9 minutes for men and women, respectively. MCT among women for BMI category I, II, and III was 14.4±6.5, 15.5±8.3, and 16.2±8.1 minutes (p=0.55), whereas for men, it was 16.3±8.9, 15.9±8.0, and 15.6±7.2 minutes (p=0.95), respectively. CONCLUSIONS: BMI had a positive association with CI time for women, but had a negative association with CI for men.