Very few studies examined the issue of regret on choosing colorectal cancer (CRC) screening tests. We evaluated the determinants of regret and tested the hypothesis that regret over screening choices was associated with poorer screening compliance. A bowel cancer screening centre invited all Hong Kong citizens aged 50-70 years who were asymptomatic of CRC to participate in free-of-charge screening programmes. Upon attendance they attended health seminars on CRC and its screening, and were offered an option to choose yearly faecal immunochemical test (FIT) for up to four years vs. one direct colonoscopy. They were not allowed to switch the screening option after decision. A self-administered, four-item validated survey was used to assess whether they regretted over their choice (> 2 = regretful from a scale of 0 no regret-5 extreme regret). A binary logistic regression model evaluated if initial regret over their choice was associated with poorer programme compliance. From 4,341 screening participants who have chosen FIT or colonoscopy, 120 (2.8%) regretted over their decision and 1,029 (23.7%) were non-compliant with the screening programme. Younger subjects and people who felt pressure when making their decision were associated with regret. People who regretted their decision were 2.189 (95% C.I. 1.361-3.521, p = 0.001) times more likely to be non-compliant with the programme. This study is the first to show that regret over the initial CRC screening choice was associated with later non-compliance. Screening participants who expressed regret over their choice should receive additional reminders to improve their programmatic compliance.