The French Dioxin and Incinerators Study was designed to estimate whether serum dioxin levels were higher in people living exposed or non-exposed to waste incinerators emissions. The study involved 1030 adults (30-65 years old) selected through a stratified two stage random sampling, from 8 locations in France. Serum analyses of PCDDs, PCDFs and PCBs were performed, and questionnaire data were collected through questionnaires. In such a study, the communication between the population and the investigators is a crucial point. Difficulties arose principally during the recruitment (complexity of the criteria for inclusion and exclusion), the blood collection and the interviews (the need for a large volume of blood required and time-consuming questionnaires), and the communication of final results (impossibility of giving a health interpretation of the dioxin serum levels). A good communication was required to face these obstacles. Early presentation of the objectives of the study and of the protocol was a key point in obtaining a favourable involvement of the population. (R.A.)