The proportion of colonoscopies with at least one adenoma (adenoma detection rate ADR) is inversely associated with colorectal cancer (CRC) risk and death. The aim of this study was to examine whether such associations exist for colonoscopy quality measures other than ADR. We used data from the Polish Colorectal Cancer Screening Program collected in 2000-2011. For all endoscopists who performed ≥100 colonoscopies we calculated detection rates of adenomas (ADR), polyps (PDR), and advanced adenomas (≥10 mm/villous component/high-grade dysplasia AADR); and number of adenomas per colonoscopy (APC) and per colonoscopy with ≥1 adenoma (APPC). We followed patients until CRC diagnosed before recommended surveillance, death, or December 31, 2019. We estimated hazard ratios (HRs) and 95% confidence intervals (CIs) using Cox proportional-hazard models. We used Harrell's C statistic to compare the predictive power of the quality measures. Data on 173,287 patients (median age, 56 years; 37.8% male) and 262 endoscopists were used. During a median follow-up of 10 years and 1,490,683 person-years, we identified 395 CRCs. All quality measures were significantly associated with CRC risk and death. The relative reductions in CRC risk were as follows: for ADR ≥24.9% (reference <12.1%; HR, 0.41; 95% CI, 0.25-0.66), PDR ≥42.7% (reference <19.9%; HR, 0.35; 95% CI, 0.24-0.51), AADR ≥9.1% (reference <4.1%; HR, 0.69; 95% CI, 0.49-0.96), APC ≥0.37 (reference <0.15; HR, 0.35; 95% CI, 0.21-0.58), and APPC ≥1.54 (reference <1.19; HR, 0.54; 95% CI, 0.35-0.83). AADR was the only quality measure with significantly lower predictive power than ADR (Harrell's C, 59.7 vs 63.4; P = .001). Similar relative reductions were observed for CRC death. This large observational study confirmed the inverse association between ADR and CRC risk and death. The PDR and APC quality measures appear to be comparable with ADR.