The objective of this study was to measure use of mammography and associated factors among women living in Spanish provinces with breast cancer screening programmes. From a cross-sectional population survey in a representative sample of Spanish women aged 40-70 years, we selected all women aged 45-65 living in provinces with breast cancer screening programmes (336 women). The programmes invited women in this age group to have a mammogram every 2 years. Data were collected by oral interviews in 1994. Use of mammography was defined as having received at least one test in the previous 2 years. Factors associated with mammography were studied using a logistic regression model. In the three autonomous communities (totalling 11 provinces) with programmes, the percentage of women receiving the test was 41.1% in Castille-Leon, 41.7% in Castille-La Mancha and 87.6% in Navarre (mean: 55.4%). The programmes began in 1990 in Navarre and between 1992 and 1993 in the other two communities. The most important factors affecting mammography use in the multivariate analysis were: intention to have a mammogram [odds ratio (OR) = 5.52; 95% confidence interval (CI) = 3.17-9.63]; not rejecting the test for fear of cancer diagnosis (OR = 4.23; 95% CI = 1.64-10.9); and physician recommendation of the test (OR = 3.43; 95% CI = 1.88-6.24). In conclusion, although the more established screening programmes have higher mammography use than those more recently implemented, programmes alone may not guarantee that women receive the test. Women's attitudes about mammography, and the role of the physician, are fundamental factors in the use of mammography.