Mammographic screening is associated with a reduced risk of breast cancer recurrence. The objective of the study was to evaluate treatment costs due to breast cancer recurrence in relation to patients' use of mammographic screening, consecutively collected in a defined population. The study included 418 women exposed to screening and 109 women unexposed to screening diagnosed with stage I-III breast cancer. During the first eight years after primary diagnosis, 19% (N=80) of the exposed women and 33% (N=36) of the unexposed women developed recurrent disease, P=0.002. In the exposed group, 41% of the 8-year treatment costs were for the treatment of patients who developed recurrent disease, compared with 52% in the unexposed group, P=0.039. Among the relapsed patients, the mean post-recurrence costs were EUR14,950, accounting for 65% of their total 8-year costs. The mean post-recurrence costs were comparable for both exposure groups irrespective of the detection method.