Previous work has established that women who attend for mammography differ from non-attenders in a number of socio-demographic and attitudinal characteristics. The present study was conducted to determine whether women who attended for mammography differed from non-attenders in a number of key areas: (1) in how they obtained information about screening; (2) in their understanding of the disease and basic screening precepts: and (3) in the extent to which they perceived their general practitioners (GPs) and other members of the primary case team, such as practice nurses, had actively promoted the programme. Three hundred attenders and 300 non-attenders were interviewed in their own homes using a structured questionnaire. Only 5% of women interviewed had ever asked their GP for any advice about breast screening, and only 18% recalled their family doctor ever discussing or raising the subject with them. Although attenders and non-attenders differed significantly in their understanding of the scope and purpose of screening, both groups obtained information more often from friends and relatives and broadcast media than fromofficialsources. Attenders were more likely to cite material in the GP's surgery as an important source of information (x2= 5.1,p= 0.02). Attenders were marginally more likely than non-attenders to have previously attended a well-woman clinic in primary care (x2= 3.1,p= 0.08) and were more likely to say that such clinics were being offered by their family doctor (x2= 9.8,p= 0.008). Attenders were no more likely to have asked for advice or to have been given counsel from their GP regarding mammography. These results suggest that women may retain information to which they are exposed in routine surgeries but that women currently attending well-woman clinics are probably a selected group unrepresentative of all those who are to be invited for screening. The majority of Northern Irish women do not actively seek advice about mammography from their family doctor.