['To determine the impact of novel invitation strategies on population participation in faecal immunochemical test (FIT)-based colorectal cancer (CRC) screening.', 'A community screening programme in Adelaide, South Australia.', 'In total, 2400 people aged 50-74 years were randomly allocated to one of four CRC screening invitation strategies: (a)', 'standard invitation-to-screen letter explaining risk of CRC and the concept, value and method of screening; (b) Risk: invitation with additional messages related to CRC risk; (c) Advocacy: invitation with additional messages related to advocacy for screening from previous screening programme participants and (d) Advance Notification: first, a letter introducing CONTROL letter messages followed by the standard invitation-to-screen. Invitations included an FIT kit. Programme participation rates were determined for each strategy relative to control. Associations between participation and sociodemographic variables were explored.', 'At 12 weeks after invitation, participation was:', '237/600 (39.5%); Risk: 242/600 (40.3%); Advocacy: 216/600 (36.0%) and Advance Notification: 290/600 (48.3%). Participation was significantly greater than CONTROL only in the Advance Notification group (Relative risk [RR] 1.23, 95% confidence interval [CI] 1.06-1.43). This effect was apparent as early as two weeks from date of offer; Advance Notification: 151/600 (25.2%) versus', '109/600 (18.2%, RR 1.38, 95% CI 1.11-1.73).'] Does an advance notification letter increase participation in colorectal cancer screening?