The purpose of this study was to examine trends in incidence and detection of ductal carcinoma in situ (DCIS) of the breast in southern Netherlands in the period 1984-2006 and assess the effect of mass screening. All patients with primary DCIS registered between 1984 and 2006 in the population-based Eindhoven Cancer Registry were included (n = 1,767). These data were linked to data from the population-based screening programme. The incidence of DCIS of the breast increased from 3/100,000 to almost 34/100,000 person-years in women aged 50-69 years in southern Netherlands since 1984. Mass screening was responsible for this increase. A stable 60% of DCIS was screen-detected. Over 11% of breast cancer patients have DCIS. In conclusion, the incidence of DCIS increased markedly in southern Netherlands with a clear effect of mammography screening since 1992.