The characteristics associated with non-attendance to mammographic breast cancer screening were studied by interviewing a random sample (213 attenders, 121 non-attenders in the 1989 screening) of residents in one of the municipalities of the Florence District Program, where screening has been ongoing since 1970. The overall attendance rate was 60%, and it was dependent on age (40-49 years, 66.5%; 50-59 years, 62.5%; 60-70 years, 55.5%), whereas a significant association with socio-economic status, educational level and health-behavior reported in other programs was not confirmed in the study. This finding suggests that determinants of non-attendance may vary and should be evaluated in each local setting. The belief that screening is useless, fear of cancer being detected, postponement and laziness were the most common motivations of refusal stated by non-attenders, and such a negative attitude towards screening was rather strong since most non-attenders stated they would not like to be informed or stimulated to attend future screenings. Rapid improvement of attendance rates in such a context might be achieved only by putting special pressure on women aimed to change their negative attitude towards screening and their opinion about the benefits of early breast cancer detection. This might be regarded as unacceptable and however would involve high costs and a major organization effort.