Objective: To evaluate the effect of implementing two modalities of organized Cervical Cancer Screening (CCS) program on screening uptake after a six-month delay. Methods: A three-armed cluster randomized control trial was conducted in France between January 8 and July 2, 2021, involving148 510 women aged 40 to 65 and 1070 general practitioners. In the Optimized screening group, an invitation letter was posted to non-adherent women, and general practitioners were sent a list of their non-adherent patients. In the Organized screening group, an invitation letter was posted to non-adherent women. In the Usual care group, no invitation was sent. The endpoint was cervical cancer screening uptake after a six months period a) among all eligible women (primary endpoint); and b) among initially non-adherent women (post-hoc analysis). Statistical analysis was based on a logistic mixed model that compared between-group percentages of adherent women. A hierarchical comparison successively tested differences between the three arms (alpha 5 % risk). Results: Among all 148,510 eligible women, screening uptake was 63.6 % (31,731/49910) in the Optimized screening group vs 61.8 % (30,210/48847) in the Usual care group (OR [IC95 %] = 1.05[0.93; 1.18]). Among the 64,370 initially non-adherent women, screening uptake was 17.9 % (3955/22134) in the Optimized screening group vs 11.6 % (5321/20995) in the Usual care group (OR [IC95 %] = 1.70[1.56;1.86]). There was no significant difference between Optimized and Organized screening groups (17.2 % vs 17.9 %; OR [IC95 %] = 1.02[0.94; 1.11]). Conclusions: The implementation of an organized screening based on an invitation letter resulted in a modest increase in participation among non-adherent women six months later.