Increasingly important objectives for developed and especially for developing countries include increasing the numbers of individuals who do not smoke, who eat healthy diets and who are physically active at levels that are health enhancing. In developing countries, deaths from chronic disease are projected to increase from 56% of all deaths in 2005 to 65% by 2030 (driven largely driven by deaths due to cardiovascular and coronary heart disease); in developed countries, however, the increase is only from 87.5 to 88.5%. The data on physical inactivity presented in this review were derived primarily from World Health Organization (WHO) publications and data warehouses. The prevalence of physical inactivity at less than the levels recommended for enhancing health is high; from 17 to 91% in developing countries and from 4 to 84% in developed countries. In developed countries, physical inactivity is associated with considerable economic burden, with 1.5-3.0% of total direct healthcare costs being accounted for by physical inactivity. Other than on some exciting work in Brazil, there is little information on the effectiveness and cost-effectiveness of physical activity-enhancement strategies in developing countries. The WHO has signaled a shift from the treatment of illness to promotion of health, with an emphasis on changing modifiable health-risk factors, including smoking, unhealthy diets and physical inactivity: the real question, especially for developing countries, is 'what is the future healthcare cost of not encouraging healthier lifestyles today?'