established and putative health, psychological, and social benefits. Exercise at lower levels of intensity and frequency may also be beneficial. However, research evidence indicates that exercise patterns are poorly maintained. This paper considers stages o f behaviour change relevant to exercise, evidence concerning the factors which influence exercise adoption and maintenance, psychological theories concerning behaviour change and maintenance, and these theories' actual and potential applications to exercise promotion. There remain a number of issues for investigation, at the levels of theory and basic research, applications in community settings, development of selfinstructional and minimal-in tervention programmes, development of public campaigns, and governmental policy development.Aerobic exercise (regular, vigorous, physical activity) has a range of Preparation of this article was supported by a grant to the second author from the Sport and Recreation Ministers' Council. The advice and support of Jim Daly, Kevin Haag, Tony Sedgwick and Tony Worsley is gratefully acknowledged.Requests for reprints should be sent to Neville Owen,