Colonoscopy surveillance after adenoma removal is an increasing burden in many countries. Surveillance recommendations consider characteristics of removed adenomas, but not colonoscopist performance. We investigated the impact of colonoscopist performance on colorectal cancer risk after adenoma removal.We compared colorectal cancer risk after removal of high-risk adenomas, low-risk adenomas, and after negative colonoscopy for all colonoscopies performed by colonoscopists with low versus high performance quality (adenoma detection rate <20% versus ≥20%) in the Polish screening program between 2000 and 2011, with follow-up until 2017. Findings were validated in the Austrian colonoscopy screening program.173,288 Polish colonoscopies were included in the study. Of 262 colonoscopists, 160 (61.1%) were low performers, and 102 (38.9%) were high performers. 11.1% of individuals had low-risk and 6.6% had high-risk adenomas removed at screening; 82.2% had no adenomas. During 10 years follow-up, 443 colorectal cancers were diagnosed. For low-risk adenoma individuals, colorectal cancer incidence was 0.55% (95%CI 0.40-0.75) with low-performing colonoscopists versus 0.22% (95%CI 0.14-0.34) with high-performing colonoscopists (HR 2.35; 95%CI 1.31-4.21; p=0.004). For high-risk adenoma individuals, colorectal cancer incidence was 1.14% (95%CI 0.87-1.48) with low-performing colonoscopists versus 0.43% (95%CI 0.27-0.69) with high-performing colonoscopists (HR 2.69; 95%CI 1.62-4.47; p<0.001). After negative colonoscopy, colorectal cancer incidence was 0.30% (95%CI 0.27-0.34) for individuals examined by low-performing colonoscopists, versus 0.15% (95%CI 0.11-0.20) for high-performing (HR 2.10; 95%CI 1.52-2.91; p<0.001). The observed trends were reproduced in the Austrian validation cohort.Our results suggest that endoscopist performance may be an additional important contributor to polyp characteristics in determining colorectal cancer risk after colonoscopy screening.