The aim of this study was to determine whether age-related differences in the accuracy of mammography breast cancer screening decrease with repeated examination. Data from the first 8 years (May 1992 to April 1999) of the Ghent breast cancer-screening programme were used for analysis. In total, 28 944 mammography examinations were included. The referral rate, cancer detection rate, positive predictive value, sensitivity and specificity were chosen as performance indicators. Values were calculated for women aged 40-49, 50-59 and 60-69 years, at initial versus subsequent examinations, respectively. For first examinations, overall, performance was much lower for the women in their forties than for the older age groups. On subsequent screening, the effect of age disappeared, as expected, or was even reversed for the positive predictive value and sensitivity of the examination. In the light of the ongoing debate over the eligible age for mammography screening, these results support a universal recommendation beginning at the age of 40 years.