This Paper describes self-administered measures of physical activity and exercise developed for the Medical Outcomes Study. The measures were designed to be appropriate for individuals with chronic medical disease and depression, enabling detection of variation at the lower end of the activity continuum including items that assess frequency and pace of walking. Included is information on how each measure was derived and summary statistics. Construct validity studies include correlations among the measures and studies of the relationship between physical activity and physical functioning. In addition, the variation in physical activity and exercise within several chronic disease groups as well as within severity subgroups is described. Variation was substantial within all subgroups, although there was some relationship between severity and activity level. Thus, it may be important to control for disease severity in outcome studies to determine the unique effects of physical activity. The measures presented here are promising for use in chronic disease populations when short, practical measures are required.