Evidence-Based Medicine (EBM) is heralded as a new paradigm of medicine. Is it? What is its link to epidemiology? Does an evidence-based (EB) approach apply also to other health sciences and to public health in particular? What has epidemiology already achieved in these domains, and what remains to be done? What should our priorities be in the coming years? The EB approach is essential in all health sciences at two levels: for problem solving, and for decision making. It applies to all health sciences, be it medicine, nursing, public health, or others. Many epidemiological principles, methods and techniques are put into good use in EBM. The EB "movement" is attractive in it's use of clearly defined procedures, generalizing (not always explicitly) the application of good epidemiologic principles, methods, and techniques. Epidemiology must now contribute to the evaluation of the practice of an EB approach. If one does not have access to a good medical library nor information technology does the EBM paradigm still hold? Hence, clinical and public health guidelines will benefit first from the EBM approach, then daily practice of EBM will follow, conditions permitting. In public health, the challenges of the EB practice are not equally spread across health protection, different levels of disease prevention, and health promotion. The latter represents the most challenging task for epidemiology at any step of EB approach. Epidemiology, if successful in this domain, may help to build an EB health promotion. An Evidence-Based Public Health paradigm may be considered. J Epidemiol, 1997; 7 : 187-197.