BACKGROUND: Colorectal cancer (CRC) risk is increased in childhood cancer survivors (CCS). In France, fecal immunochemical testing (FIT) is recommended every 2 years for those aged 50-74 years, although no specific CRC-screening programs are dedicated to CCS. METHODS: We investigated the participation rate in CRC screening by using the national health data system to identify FIT in the French Childhood Cancer Survivor Study cohort, across three two-year periods-2016-17, 2018-19, and 2020-21-to compare it to the general population via indirect standardization and used multivariable logistic regression to investigate factors influencing CCS participation. RESULTS: In 2016-17, 2018-19, and 2020-21, respectively, 20.0%, 21.8%, and 23.2% participated in screening, which is lower than the rate for the general population [standardized incidence ratios (95% CI) = 0.62 (0.49-0.78), 0.72 (0.59-0.87), and 0.70 (0.59-0.83), respectively]. Demographic, clinical, therapeutic, and socio-economic determinants were not associated with CRC-screening participation. Although these patterns were not consistently observed across all subgroups, survivors with severe long-term complications tended to have higher participation [odds ratio (95% CI) = 1.64 (1.07-2.53)], whereas higher medical expenses were associated with lower participation (P < .01). CONCLUSION: Despite an increased risk of CRC after childhood cancer, participation in CRC-screening programs remains low in CCS. Survivors and their physicians require educational initiatives to promote CRC screening and provide risk-adapted surveillance guidelines.