BACKGROUND: Performing colonoscopies is an integral component of colorectal surgery residency training. There exists a paucity of literature regarding colonoscopy quality metrics with colorectal trainee involvement. OBJECTIVE: This study aimed to investigate the effect of colorectal surgery resident participation on quality metrics in screening colonoscopy. DESIGN: Screening colonoscopies performed between August 1, 2016, and July 31, 2018, were queried from a prospectively maintained institutional database. Data were cross-checked with resident case logs to verify colonoscopies with resident participation. SETTING: This study was conducted by the colorectal surgery department at a tertiary level hospital in the United States. PATIENTS Consecutive, asymptomatic patients aged >= 45 years, undergoing screening colonoscopy, were selected. MAIN OUTCOME MEASURES: The quality parameters measured included overall, male, and female adenoma detection rates; total examination time; withdrawal time; cecal intubation rate; quality of bowel preparation; complications; and medication dosage. RESULTS: A total of 4594 patients were included in the study with a mean age of 60.5 +/- 8.4 years (range, 45-91); 51.7% were women. Overall, 4186 of the colonoscopies were performed without resident participation, and 408 were performed with resident participation. Scope insertion, withdrawal, and total examination times were longer in the resident group. Cecal intubation rate, polypectomy rate, sex-specific and overall adenoma detection rates, and complication rates were similar between the groups. In the multivariate model, trainee involvement had no significant impact on adenoma detection rate. In addition, the trainee group utilized a higher mean dose of fentanyl. LIMITATIONS: The retrospective nature of the data with possible coding errors of the database and the inability to quantify the amount of resident participation and to clarify the degree of attending surgeon assistance and oversight were limitations of the study. CONCLUSIONS: Colorectal surgery resident participation in screening colonoscopy takes longer and appears safe, while achieving all national quality metrics without compromising adenoma detection rates. Changes in colonoscopy scheduling in regard to length of time may prove beneficial when there is resident participation. See Video Abstract at http://links.lww.com/DCR/B43.