BACKGROUND: For evaluation of breast cancer screening and informed prioritisation, it is important to examine the downstream healthcare use associated to participation. The objective of this study is to determine the healthcare use among breast cancer screening participants compared with screening-naïve controls. METHODS: The study is a register-based cohort study with 14 years of follow-up. We compare healthcare use among women who participated in the initial phase of the stepwise breast cancer screening implementation in Denmark (stratified on screening result: normal, false positive and breast cancer) compared with those invited in subsequent phases. RESULTS: Screening participants, especially those with false-positive results, tended to use primary healthcare services more than the screening-naïve group. Women with breast cancer and false positives received more breast imaging compared with the screening-naïve group. False positives consistently had the highest use of drugs compared with the control group. All screening groups had significantly higher use of outpatient clinic visits in the year of and following screening compared with the screening-naïve group. Screening groups were more likely to receive additional diagnoses in the years following screening than the screening-naïve group. There were no significant differences in medical procedures and days of hospitalisation. CONCLUSIONS: The study highlights differences in primary healthcare use among screening groups compared with the screening-naïve group. Since use of primary care services is at the discretion of the women, this implies increased worries about health. Thus, these results indicate increased healthcare-seeking behaviour, especially among women with false-positive results.