Cancer screening is a source of much debate. At the interface between public health, specialist care, economics and policy, it creates tensions between professional groups, politicians, the media and the public. A screening test may be cheap, but applying it to a population (with rigorous quality control and effective processing of patients with abnormal results) creates a huge workload and therefore cost. Screening can also have profound psychological effects on individuals. People with false-positive results require investigation and yet are usually found eventually not to have cancer. Unless screening can be shown to reduce mortality from a specific cancer, the resources used are better spent on improving care, and this has led to disparities in screening recommendations between countries. Advances in our understanding of the genetic basis of cancer are likely to provide both new approaches to cancer risk assessment and new challenges for developing screening strategies, by risk banding populations based on polymorphisms in low-penetrance cancer risk genes. The American Cancer Society reviews its guidelines for cancer screening annually. These represent a global gold standard that is difficult to emulate in most healthcare economies.