Women who attend for breast screening are in general not motivated by ill health. The benefit of any such programme depends upon repeated use and satisfied clients are more likely to continue the relationship with their health care provider. However, evaluation of satisfaction with the service is impeded by the lack of a specific tool for use within this target population. The purpose of the present study was to develop and conduct preliminary testing of the properties of a customer satisfaction measuring instrument (CSMI) that reflected aspects of importance to the users and providers of the breast screening service, hence ensuring content validity of the tool. Development and testing involved four studies and resulted in a 23 item CSMI, which comprised six dimensions addressing location, arrival at the unit, the mammogram, the breast screening service, the staff and information.