Objective: To describe how scientific evidence has influenced healthcare policy making in Belgium in the field of sickness prevention for mammography, PSA testing in prostate cancer screening, and use of ultrasound in pregnancy.

Methods: Review of published and gray literature and interviews with stakeholders and experts.

Results: At the end of 1999, a systematic national/regional screening program had not yet been implemented for any of the three screening strategies. A systematic breast cancer screening program is being prepared for implementation only in Flanders. This limited impact can be attributed to the fragmentation in healthcare policy, the different options among the different regions, fragmentation in healthcare practice, the strong impact of healthcare stakeholders (provider groups and sickness funds) on decision making, and limited attention to scientific evidence in health policy and technology assessment.

Conclusions: Health technology assessment has had very little impact on policy and practice in use of mammography, PSA testing, and ultrasound in pregnancy in Belgium.