The Finnish National Asthma Program 1994-2004 markedly improved asthma care in the 1990s. We evaluated the changes in costs during 26 years from 1987 to 2013. Direct and indirect costs were calculated by using data from national registries. Costs from both the societal and patient perspectives were included. The costs were based on patients with persistent, physician-diagnosed asthma verified by lung function measurements. We constructed minimum and maximum scenarios to assess the effect of improved asthma care on total costs. The number of patients with persistent asthma in the national drug reimbursement register increased from 83,000 to 247,583. Improved asthma control reduced health care use and disability, resulting in major cost savings. Despite a 3-fold increase in patients, the total costs decreased by 14%, from €222 million to €191 million. Costs for medication and primary care visits increased, but overall annual costs per patient decreased by 72%, from €2656 to €749. The theoretical total cost savings for 2013, comparing actual with predicted costs, were between €120 and €475 million, depending on the scenario used. The Finnish Asthma Program resulted in significant cost savings at both the societal and patient levels during a 26-year period.