Colorectal cancer is the second most common cancer in Algeria. Its screening is of interest which was confirmed in a Cochrane meta-analysis. The national organized screening program for colorectal cancer has been validated by the national screening committee but not yet implemented in Algeria. a pilot study was carried out in the Bejaïa region between January 2017 and December 2019. It is aimed, every two years, at people aged 50 to 74 at average risk and asymptomatic. It has since been based on the immunological test for occult blood in the stool. The participation rate for this pilot program was 33%, lower than European recommendations. In our study, the citizen participation rate was the main judgment criterion. The objective of this work was to evaluate the impact factors of the pilot program identified during its implementation. Results taking a test under the program is associated with a reduction in the lifetime risk of developing colorectal cancer, by 24% for men and 21% for women, and a reduction in the risk of die from colorectal cancer, by 51% and 43% respectively. The mass screening strategy is based on steps according to a process model, it was identified that awareness had a positive impact with a;;;; training was also identified as a positive impact factor on the participation of general practitioners. Conclusion these results confirm that in the average risk population, screening organized is an effective strategy for reducing the risk of colorectal cancer. They also confirm that achieving European objectives remains a key issue for improve the effectiveness of organized screening. An evolution of the test delivery methods immunological could make it possible to achieve these participation objectives.