The organized breast cancer screening program, launched in Paris in 2003, offers advantages in terms of quality control and evaluation compared to the individual screening approach with which it coexists. The Osapiens survey (Observatory of Parisian Health), conducted in 2006, surveyed a representative sample of 442 Parisian women regarding their use of mammography. Women aged 50 to 74 at the time of their last mammogram were asked about their screening practices to better describe the profiles of women who use individual screening or organized screening. Among the target population, 75.4% [67.1–82.2] of women reported having undergone a screening mammogram in the previous two years. Only 27.3% [22.9–32.1] participated in organized screening. Motivations for screening vary by type of screening: women who underwent organized screening (vs. individual screening) reported being more motivated by information campaigns (54.2% vs. 15.9%, p=0.01) as well as by a close relative having cancer (19.3% vs. 4.2%; p<0.01). Regular gynecological follow-up appears to be the main determinant of screening, whether individual or organized OR=8.0 [4.7-13.6]. Non-smokers also participate more frequently, as do those reporting the highest levels of education. This trend based on educational level suggests a difference in socioeconomic profiles between users of individual screening and organized screening. (R.A.)