Background: One of the suggested benefits of cancer screening is the peace of mind and reassurance experienced by those women who are given negative results. The aim of the present study was to investigate whether there was a difference in the expression of psychosocial aspects in a population of women offered screening compared to a population of women not offered screening for breast cancer. Methods: One thousand women, aged 50—69 years, were randomly drawn from the Danish Civil Registration System to receive part I of the questionnaire Consequences of Screening in Breast Cancer (COS-BC1): the sample consisted of 500 women living in a geographical area where screening mammography had been offered for more than 10 years and 500 women living in an area where the public health authorities had never invited women to breast cancer screening. Results: A total of 759 women returned the questionnaire. Those living in areas where screening was not offered reported more negative psychosocial aspects compared to women living in areas where screening was offered. Conclusions: The results indicate that women tend to perceive breast cancer screening as a reassuring preventive initiative. Alternatively, the results indicate that the lack of invitation to breast cancer screening may have a negative psychosocial impact.