Aim: To conduct a systematic review of epidemiological studies on phthalate exposure, including a request for the study proposal (protocol) and to study determinants of protocol provision. Methods: A literature search was carried out to identify epidemiology studies on phthalate exposure. In addition reference lists and reviews were searched for eligible publications. Corresponding authors were asked to participate in a short telephone interview and to provide a copy of the study proposal (protocol). Study characteristics were scored and their association with protocol provision examined.