The success rate for reaching the cecum has been widely discussed as an indicator of technical expertise for colonoscopy. However, few studies have addressed the impact of endoscopist-specific parameters on cecal intubation rates. The aim of this study was to characterize the relationship between endoscopist-specific parameters (age, gender, experience level, annual procedure volume, insertion and withdrawal times) and cecal intubation rates for colonoscopy. Procedural data from all colonoscopies performed by gastroenterologists at the outpatient endoscopy unit of Rochester Methodist Hospital, Minnesota, between January and December 2003 were reviewed. Procedural data of 45 endoscopists who performed 17,100 colonoscopies over the study period were analyzed. The average cecal intubation rate was 93.9% (SD, 2.9%). Higher experience level (>9 years [median]) was significantly predictive of a cecal intubation rate >94% (OR = 3.43; 95% CI, 1.03-12.29; P = 0.04). Although higher procedure volume was not predictive of higher colonoscopy completion rates overall, when analysis was confined to the junior faculty members (<5 years' experience), completion rates for those endoscopists doing >200 per year (92.5%) was significantly higher than for those doing <200 per year (88.5%; P = 0.04). Our observations suggest that cecal intubation rates increase with increasing endoscopist experience. Moreover, among junior endoscopists, an annual volume of at least 200 procedures appears to be required to maintain adequate competence. Future prospective studies should provide data to support consensus guidelines recommending minimum annual procedure numbers required for maintenance of endoscopic competence among trained endoscopists.