Background:Randomised trials show reduced colorectal cancer (CRC) mortality with faecal occult blood testing (FOBT). This outcome is now examined in a routine, population-based, screening programme.Methods:Three biennial rounds of the UK CRC screening pilot were completed in Scotland (2000-2007) before the roll out of a national programme. All residents (50-69 years) in the three pilot Health Boards were invited for screening. They received a FOBT test by post to complete at home and return for analysis. Positive tests were followed up with colonoscopy. Controls, selected from non-pilot Health Boards, were matched by age, gender, and deprivation and assigned the invitation date of matched invitee. Follow-up was from invitation date to 31 December 2009 or date of death if earlier.Results:There were 379?655 people in each group (median age 55.6 years, 51.6% male). Participation was 60.6%. There were 961 (0.25%) CRC deaths in invitees, 1056 (0.28%) in controls, rate ratio (RR) 0.90 (95% confidence interval (CI) 0.83-0.99) overall and 0.73 (95% CI 0.65-0.82) for participants. Non-participants had increased CRC mortality compared with controls, RR 1.21 (95% CI 1.06-1.38).Conclusion:There was a 10% relative reduction in CRC mortality in a routine screening programme, rising to 27% in participants.British Journal of Cancer advance online publication, 26 June 2012; doi:10.1038/bjc.2012.277 www.bjcancer.com.