AIMS: Physical activity has consistently been shown to improve cardiovascular health and high-density lipoprotein-cholesterol levels. However, only small and heterogeneous studies have investigated the effect of exercise on high-density lipoprotein functions. Our aim is to evaluate, in the largest observational study to date, the association between leisure time physical activity and a range of high-density lipoprotein functional traits. METHODS: The study sample consisted of 296 Spanish adults at high cardiovascular risk. Usual leisure time physical activity and eight measures of high-density lipoprotein functionality were averaged over two measurements, one year apart. Multivariable linear regression models were used to explore the association between leisure time physical activity (exposure) and each high-density lipoprotein functional trait (outcome), adjusted for cardiovascular risk factors. RESULTS: Higher levels of leisure time physical activity were positively and linearly associated with average levels over one year of plasma high-density lipoprotein-cholesterol and apolipoprotein A-I, paraoxonase-1 antioxidant activity, high-density lipoprotein capacity to esterify cholesterol and cholesterol efflux capacity in individuals free of type 2 diabetes only. The increased cholesterol esterification index with increasing leisure time physical activity reached a plateau at around 300 metabolic equivalents.min/day. In individuals with diabetes, the relationship with cholesteryl ester transfer protein followed a U-shape, with a decreased cholesteryl ester transfer protein activity from 0 to 300 metabolic equivalents.min/day, but increasing from there onwards. Increasing levels of leisure time physical activity were associated with poorer high-density lipoprotein vasodilatory capacity. CONCLUSIONS: In a high cardiovascular risk population, leisure time physical activity was associated not only with greater circulating levels of high-density lipoprotein-cholesterol, but also with better markers of high-density lipoprotein functionality, namely cholesterol efflux capacity, the capacity of high-density lipoprotein to esterify cholesterol and paraoxonase-1 antioxidant activity in individuals free of diabetes and lower cholesteryl ester transfer protein activity in individuals with type 2 diabetes