Introduction – In mainland France (including Corsica), organized colorectal cancer screening involves a fecal occult blood test every two years for people aged 50 to 74. In the event of a positive result, a colonoscopy is recommended within 31 days. However, it is often performed later and is sometimes not performed at all. The objective of this study is to identify the factors associated with undergoing a colonoscopy at three time points: 1, 3, and 24 months after a positive FIT (Fecal Immunochemical Test).Method – The study focuses on individuals with a positive FIT result in mainland France between 2016 and 2020. Data on whether or not a colonoscopy was performed at each of the three time points were collected. Logistic regression models were fitted to estimate the factors associated with failure to undergo colonoscopy. Results – Among the 530,674 individuals studied, 4.7% had undergone colonoscopy at 1 month, 52.2% at 3 months, and 87.0% at 24 months following the FIT. In multivariate analysis, factors associated with failure to undergo colonoscopy at 24 months were age, male sex, first-time screening, social deprivation, and failure to transmit FIT results to the primary care physician. Conclusion – Significant inequalities persist in access to colonoscopy following a positive FIT, both in the short and long term. These results call for the implementation of specific measures to improve follow-up after screening, particularly among vulnerable populations.