Objective. To present the results of the evaluation of the National Organized Breast Cancer Screening Program for the period 2004–2009. Materials and methods. The data analyzed were drawn from the national organized screening database (DO) and pertain to women aged 50 to 75 residing in mainland France at the time of their screening, from 2004 to 2009. Indicators of activity, quality, and early effectiveness were calculated with their 95% confidence intervals and standardized by age. The results are presented according to screening round, taking into account individual screening history (IS). Linear trend tests over time were calculated using a Poisson regression model adjusted for age and department. Cancer data for 2009 are provisional. Results. The rate of positive screening results prior to diagnostic evaluation was 9.2 per 1,000 women screened in 2009, and the rate of cancers ultimately detected was 6.9 per 1,000 women screened in 2008. The second reading, performed only on mammograms deemed normal or benign, yields a positive screening rate prior to diagnostic evaluation of 1.3 per 1,000 screened women, and a cancer detection rate of 0.44 per 1,000 screened women. Significant decreases in these rates have been observed since 2004. The rates of cancers with a good prognosis were 1.06 in situ cancers, 1.95 small invasive cancers, and 3.87 invasive cancers without lymph node involvement per 1,000 women screened in 2008. These rates show slight but significant decreases since 2004, but stable trends in terms of the proportion of cancers detected. The positive predictive value (PPV) of positive screening results prior to diagnostic evaluation was 7.3% in 2008 and has increased significantly since 2004. However, these results vary depending on the screening round, with significantly higher values for a first screening within the DO program in the absence of a reported history of ID. Discussion and conclusion. Overall, the results show values consistent with the levels recommended by European guidelines. They indicate slight trends, generally suggesting an improvement in the screening procedure, but over a short period of time during which screening procedures and techniques remained stable. This assessment should be repeated, particularly to evaluate the introduction of digital mammography into this program. (R.A.)