The aim of this study was to assess participants' satisfaction in an epidemiological research project. The questionnaire included 7 closed questions (concerning organisation, reception, and information) and 3 open-ended questions (regarding motivations, and expectations). In this multi-faceted epidemiological study on asthma, the questionnaire's acceptance was high (298 responses received/328 questionnaires). The organisation of the survey was considered satisfactory overall. The usefulness of the documentation received and the demand for further information were two points which were frequently underlined by the participants. These results demonstrate the necessity of improving information provided to participants, as well as the need to adjust and implement better, more detailed instruments to assess the satisfaction in epidemiological surveys.