IntroductionThe participation rate is higher in breast cancer screening than in cervical cancer (CCU) and colorectal cancer (CRC) screening. In this cluster-randomised study, we aim to evaluate an intervention offering home-based CCU and CRC screening to women when attending breast cancer screening if they are overdue for CCU and/or CRC screening.Methods and analysisOn intervention days, one of the five breast cancer screening units in the Central Denmark Region will be randomly allocated to intervention, whereas the remaining units will serve as control. Women attending breast cancer screening in the intervention unit will be offered information regarding their CCU and CRC screening history, and, if overdue, they will be offered self-sampling screening kits. For CCU screening, women aged 50–64 years will be offered a vaginal self-sampling kit for human papillomavirus testing. For CRC screening, women aged 50–69 years will be offered a kit to obtain a faecal immunochemical test. Women attending the control units will receive only standard care.After the intervention, a survey will be sent to all women in the intervention and control group, asking about their experience while attending breast cancer screening.Primary outcomes will be difference in the coverage in CCU and CRC screening 6 months after intervention between the intervention and the control group, and difference in participation rates 6 months after intervention for those who were overdue for CCU and/or CRC screening at the time of the intervention.Ethics and disseminationThe project is listed in the record of processing activities for research projects in the Central Denmark Region (R. No.: 1-16-02-217-21). According to the Danish Consolidation Act on Research Ethics Review of Health Research Project, this study was not notifiable to the Committee (R. No.: 1-10-72-1-21). The findings will be disseminated in peer-reviewed scientific journals.Trial registration numberNCT05022511.