This thesis investigates computerised cognitive training in older adults, with a focus on training working memory and fluid intelligence. A series of studies is reported, with two broad aims. The first was to develop and validate outcome measures appropriate for use in this population, and the second was to examine whether established gains in cognitive functioning generalised to everyday life. In relation to the first aim, two studies were conducted which concerned the development of a sensitive measure of organisational abilities within a computerised paradigm, the Games Evaluation Task (GET). A further study made use of an existing naturalistic measure, the Multiple Errands Task (MET, Shallice & Burgess, 1991), and investigated whether it was possible to obtain reliable ratings of performance on the basis of video footage taken from the participant’s perspective by means of a body-worn camera. Both the GET and MET were used as outcome measures in the subsequent training studies. In relation to the second aim, three studies of cognitive training are reported. The first is a case study of a man with problems in working memory and time perception following a stroke. He underwent training on an intensive working memory package within a single-case experimental design that incorporated an active control condition. This approach was then extended in a larger sample of healthy older adults, who trained intensively on tasks that focussed either on working memory, or fluid intelligence and problem solving. In the final study participants trained on a combination of both working memory and fluid intelligence tasks. In addition, they watched training videos that focused on teaching various cognitive strategies. The aim of this video supplement was to help participants draw links between the computer training and real-life situations, and hence to foster generalisation of any benefits to everyday life. The thesis concludes with a general discussion which examines the major findings of the studies presented, their clinical applications, the limitations of the research and possible future directions.