BACKGROUND: Colorectal cancer is the third most common type of cancer in Brazil, despite the availability of screening methods that reduce its risk. Colonoscopy is the only screening method that also allows therapeutic procedures. The proper screening through colonoscopy is linked to the quality of the exam, which can be evaluated according to quality criteria recommended by various institutions. Among the factors, the most used is the Adenoma Detection Rate, which should be at least 25% for general population. AIMS: To evaluate the quality of the screening colonoscopies performed in a quarternary private Brazilian hospital. METHODS: This is a retrospective study evaluating the quality indicators of colonoscopies performed at a private center since its inauguration. Only asymptomatic patients aged over 45 years who underwent screening colonoscopy were included. The primary outcome was the Adenoma Detection Rate, and secondary outcomes included polyps detection rate and safety profile. Subanalyses evaluated the correlation of endoscopic findings with gender and age and the evolution of detection rates over the years. RESULTS: A total of 2,144 patients were include with a mean age of 60.54 years-old. Polyps were diagnosed in 68.6% of the procedures. Adenoma detection rate was 46.8%, with an increasing rate over the years, mainly in males. A low rate of adverse events was reported in 0.23% of the cases, with no need for surgical intervention and no deaths. CONCLUSIONS: This study shows that high quality screening colonoscopy is possible when performed by experienced endoscopists and trained nurses, under an adequate infrastructure.