This publication seeks to provide an overview of epidemiological public health research (EPHR) undertaken in the UK and the United States during the twentieth century, and to show how this work has contributed to the development of public health policy. Other aspects discussed include: the structure, organisation and funding of public health research in the two countries during this period, key political and social concerns at this time, factors influencing the quantity and quality of EPHR and possible reasons for the variability of research output. In addition, the annexes highlight the political aspects of EPHR by looking at two specific examples: research carried out in the former German Democratic Republic before and after the fall of the Berlin Wall; and the investigation of BSE in the UK.