The success of any health-related screening programme depends primarily upon behavioural factors, namely whether people attend, and for those who do attend, the cognitive, emotional and behavioural consequences of doing so. Some of the problems now evident in screening programmes, such as low attendance or high levels of anxiety following participation are due in part to an under-investigation of the psychological processes and outcomes critical to achieving the goals of screening programmes. These goals include high rates of informed participation and satisfactory psychological outcomes of such participation. The development of psychological models in this area may help in documenting the factors mediating and moderating responses to screening, and may suggest interventions likely to facilitate the achievement of the goals of a screening programme.