OBJECTIVE: To assess the association between residential area-level deprivation, individual life-course socioeconomic position and adult levels of physical activity in older British women. METHODS: A cross-sectional study of 4286 British women aged 60-79 years at baseline, who were randomly selected from general practitioner lists in 23 British towns between April 1999 and March 2001 (the British Women's Heart and Health Study). RESULTS: All three of childhood socioeconomic position, adult socioeconomic position and area of residence (in adulthood) deprivation were independently (of each other and potential confounders) associated with physical activity. There was a cumulative effect of life-course socioeconomic position on physical activity, with the proportion who undertook no moderate or vigorous activity per week increasing linearly with each additional indicator of life-course socioeconomic position (p<0.001 for linear trend). CONCLUSION: Adverse socioeconomic position across the life-course is associated with an increased cumulative risk of low physical activity in older women. Reducing socioeconomic inequalities across the life course would thus be expected to improve levels of physical activity and the associated health benefits in later life.