Objective : The breast cancer screening programme, proposed to all women between 50 and 69 years, consisting of two-view mammography screening every two years, has been generalized in France since 2004. The programme coexists with opportunistic mammography screening, provided outside official frameworks. This qualitative study was designed to identify the pros and cons of these two screening modes. Methods : Three hundred and forty-five women were randomly selected from women who had participated in a previous quantitative study and who were invited to attend for breast cancer screening in 13 French departments between 2010 and 2011. These women were asked to participate in a face-to-face semistructured interview conducted by a sociologist. Results : 48 women (17 from deprived areas) were interviewed. All chose to be screened for breast cancer either because they feared cancer, or because they wanted to control their own health. Twenty-seven women chose the organized screening programme, which they considered to be trustworthy, as negative mammograms are double checked by a second radiologist. Twenty-one women preferred individual screening, which they considered to be more reliable, less anonymous and providing them with more liberty to take control of their own health. Conclusion : Gynaecologists play an important role in women’s decision to undergo individual breast cancer screening. They also have an important role to play in the promotion of organized breast cancer screening programme with this public.