The success of cardiovascular disease (CVD) risk factor screening programmes depends heavily on good uptake rates and the extent of risk factors modification following screening. It is thus important to try to understand what affects people's decision to attend a screening appointment and their motivation to change their lifestyle, if necessary, following screening. This paper summarises three studies undertaken to describe uptake of screening and risk factor modification and to identify the psychological factors involved. The studies took place in two settings: a worksite mobile screening service and a city health centre screening programme. The results identified a number of sociodemographic, personal and organizational factors involved in screening behaviour which offer suggestions for effective planning of screening programmes.