The National Organized Colorectal Cancer Screening Program (PNDOCCR) allows people aged 50 to 74 to undergo a fecal occult blood test every two years, upon invitation. Certain individuals are excluded from the program, particularly those who have previously undergone a colonoscopy. Each year, Santé publique France publishes exclusion and participation rates for the program based on data from the regional cancer screening coordination centers (CRCDC). Since the information collected on procedures performed is incomplete, exclusion rates are underestimated and vary widely from one department to another. The objective of this article was to estimate these rates using data from the National Health Data System (SNDS) and to assess the impact of this estimation on participation rates. In 2018, the national exclusion rate according to the SNDS reached 19.2% (ranging from 10.8% to 24.7% depending on the department), and the participation rate was 39.8% (37.1% according to CRCDC data). A more accurate estimate of exclusion rates automatically increases participation rates. However, even when recalculated more precisely, these rates remain too low in France, still falling short of the minimum rate recommended by the European Union (45%), and regional disparities persist.