Background and aim: the success of colorectal cancer (CRC) screening programmes largely depends on the quality of the events, processes and outcomes and therefore, quality assurance of endoscopy is an essential component. The quality indicators for colonoscopy in a screening programme setting are different from those performed in symptomatic people. The objective of this study was to report the main quality indicators of colonoscopies performed after a positive faecal occult blood test (FOBT) in a CRC screening programme in Catalonia. Methods: the period of study includes three rounds of the CRC screening programme from June 2006 to July 2013. Two types of FOBT were used: a qualitative biochemical guaiac-based test (gFOBT) and a quantitative immunochemical test (FIT). Quality indicators analysed in this study were compared to recommended colonoscopy standards from the published guidelines. Results: during the study period, 1,806 colonoscopies were performed in 1,691 individuals with a positive FOBT. All indicators were within the standard except waiting time to colonoscopy. Caecal intubation rate was 95.6 % and adequate bowel cleansing 93.6 %. Adenoma detection rate was better using FIT than gFOBT, 30.7 and 3.8 per 1,000 screenees, respectively. Cancer detection rate was also greater using FIT. Nearly 62 % of cancers were diagnosed at an early stage. The overall complication rate was 10.7 . Conclusion: although the majority of results reached the recommended standards, some areas have been identified for quality enhancement. Continuous monitoring of quality indicators is essential for improving the current effectiveness of CRC screening programmes.