A lifetime cost-effectiveness analysis was developed to evaluate the costs, health gains, and cost-effectiveness (dollars per quality-adjusted life year [QALY] gained, relative to no intervention) of seven population-wide strategies to promote physical activity in healthy adults. All of the interventions were found to be cost-effective in reducing coronary heart disease, ischaemic stroke, colorectal and breast cancers, and type 2 diabetes. Cost-effectiveness ratios ranged between $US14,000 and $US69,000 per QALY gained, relative to no intervention.