Using patient-identifiable data for epidemiological research. The use of patient-identifiable data in epidemiological research is subject to increasingly complex regulation. This article reports the experience of a research team in setting up the Epidemiology and Survival of Transfusion Recipients (EASTR) study in which patient-identifiable information was needed in order to link data from two sources for analysis and obtain long-term survival patterns of transfusion recipients. The process of establishing the study involved obtaining separate ethical, research and development and data protection approval, including application to the newly formed Patient Information Advisory Group, set up under Section 60 of the Health and Social Care Act, 2001. We describe the high cost in administrative procedures and time now necessary to gain statutory approval before such a study can begin, which has been the result of recent legislation. Issues arising from our experience are discussed.