The concept of screening in health care – that is, actively seeking to identify a disease or pre-disease condition in individuals who are presumed and presume themselves to be healthy – grew rapidly during the twentieth century and is now widely accepted in most of the developed world. Used wisely, it can be a powerful tool in the prevention of disease. But it is essential to observe the long-established principles and criteria and resist the introduction of screening practices that do not meet these requirements. We begin this summary by outlining the historical background to screening and by looking at some definitions of the practice based on experience in the United States and the United Kingdom but relevant more widely. We go on to examine the criteria for screening and its evaluation and the benefits and disadvantages of the practice. We then consider a number of key issues that are relevant at all stages and to every type of screening in any country. Finally, we look at current screening practices within the European Union (EU), using the United Kingdom as a model, before drawing a number of general conclusions.