The programme "Europe against cancer" stimulated, among other activities, breast screening activities in the member states. From the beginning, it was clear that a rigorous and efficient approach required the highest possible quality of the three major components of a breast screening programme: the medical performance (correct positioning, training of the medical staff, double reading of the mammograms and feedback from the pathologist and the epidemiologist), the organisation (attendance rate, data base) and the quality of the imaging process (compliance of the image quality and the breast dose with the CEC document of 1990). The first part of this paper will be limited to the latter component and the second part to the subject of correct positioning of the breast.