Accepted for publication 6 October 1998 In the United Kingdom, levels of physical activity in the general population are low1 and there is great potential for improving public health by promoting physical activity.2 To achieve this health professionals need to have a good understanding of the principal barriers that operate and, in a UK study of people aged 16-74 years these included lack of time or rec reational facilities, poor motivation, and ill health.1 Barriers vary by age13 and social class3 but knowledge of variation with other measures of socioeconomic position is scarce. We studied the relation between perceived barriers to physical activity, socioeconomic position, and other social characteristics in men and women aged 16-74 years. Methods Data for this study come from the Newcastle Health and Lifestyle Survey,4 which was a postal survey of a 1 in 30 sample, stratified by age and sex, of 6448 adults aged 16-74 years identified from the Family Health Services Authority register. Between October 1991 and March 1992 a self completion questionnaire was used to collect data on health related behaviours, socioeconomic position, health status, and knowledge and attitudes to health issues. With respect to physical activity re spondents were asked if they did enough exer cise for someone of their age and those who answered "no" were asked to identify perceived barriers from a list of eight commonly reported