Few medical students gain practical experience in practical epidemiology during their undergraduate years or understand how this science is a prerequisite to decision-making in the health services. In an attempt to overcome this deficit a group of clinical students was asked to measure the incidence of cerebrovascular disease in the Cape Peninsula over a relatively short period in order that rehabilitation facilities could be planned for affected patients. The exercise proved extremely fruitful for both the staff and the students. For the latter it not only met the objectives outlined above but also forced them to enter the community and so gain a perspective of all health services provided. We suggest that this technique, which can be applied to many topics, is a useful way of introducing students to these important concepts.