OBJECTIVES: The EU recommends biennial breast cancer screening for women 50 - 69 of age. If 1,000 women are biennial screened in ten years 20 - 30 women are diagnosed with breast cancer. The reduction of the breast cancer mortality will shift for one woman only; the other 19 - 29 women diagnosed with breast cancer will die or survive regardless of the screening. In five rounds of breast cancer screening more than 100 women will experience to get a false-positive screening mammography. Women recalled for further investigations after an abnormal screening mammography, which after diagnosis is confirmed to be a false-positive result, experience significant adverse psychosocial consequences. METHODS: A prospective longitudinal survey over one year from June 2004 included consecutively women who participated in breast cancer screening. A validated questionnaire, Consequences Of Screening on Breast Cancer (COS-BC), specifically developed for measuring psychosocial consequences of abnormal and false-positive screening mammography was used as outcome measure. Previously Rasch analyses have confirmed that COS-BC encompasses four subscales and three single items. The COS-BC was completed by women with an abnormal screening mammography and women with a normal screening mammography and the psychosocial impact in these two groups was compared. RESULTS: All together 453 women with an abnormal screening mammography and 845 women with a normal screening mammography completed the COS-BC. In all four dimensions and in the three single items differences were found. Women with an abnormal screening mammography had experienced more negative psychosocial consequences compared to women with a normal screening result. All differences were statistically significant with p-values were less than 0.001. CONCLUSION: It has severe psychosocial consequences to have an abnormal screening mammography, which ought to be taken into account when planning breast cancer screening.