BACKGROUND AND STUDY AIM: International studies have shown differences in the outcome of screening colonoscopies related to the endoscopist's specialty and setting of colonoscopy. The aim of this study was to investigate the impact of these two factors on quality parameters for screening colonoscopy in a quality-assured screening program. METHODS: Adenoma detection rate (ADR), cecal intubation rate (CIR), polypectomy rate, flat polyp detection rate, carcinoma detection rate, sedation rate, complication rates, and other parameters of 59 901 screening colonoscopies performed by 178 endoscopists were analyzed in relation to specialty (35 gastroenterologists: 10 066 colonoscopies [16.8 %]; 84 nongastroenterologists: 26 271 colonoscopies [43.9 %]; 59 surgeons: 23 564 [39.3 %]), and setting (hospital: 12 580 [21.6 %] colonoscopies; office: 45 781 [78.4 %] colonoscopies). RESULTS: The overall ADR was 20.5 % and the CIR was 95.6 %. The ADR did not show any statistical significance, either in relation to specialty or to setting. A significant difference in the CIR was found between hospital-based and office-based internists (98.5 % vs. 96.8 %, respectively; P  = 0.0005; odds ratio [OR] 2.2, 95 % confidence interval [CI] 1.4 - 3.4). Hospital-based internists had a significantly higher flat polyp detection rate (7.5 % vs. 4.1 %; P  = 0.02; OR 1.9, 95 %CI 1.1 - 3.2) and a significantly lower carcinoma detection rate (0.4 % vs. 0.6 %; P  = 0.03; OR 0.7, 95 %CI 0.5 - 1.0) compared with office-based internists. Complication rates were significantly lower among surgeons than among internists (0.1 % vs. 0.2 %; P  = 0.03; OR 0.5, 95 %CI 0.3 - 1.0). CONCLUSION: Endoscopists participating in the Austrian quality assurance program offered high quality screening colonoscopy regardless of their specialty and setting. The implementation of a standardized quality program is therefore a decisive factor in quality improvement of screening colonoscopy.