OBJECTIVES Asthma is one of the mostly seen chronic illnesses in Turkey, yet there are limited studies on cost of asthma in our country. In addition they were based on a central database and weight of disease. The aim of this study was estimating the nationwide cost of managing asthma and examining its variability depending on asthma control level. METHODS The clinical pathway for asthma was determined from the literature. Part of the data was collected from the expert’s clinical view. To calculate the direct costs, the medical management of adult asthma was estimated using 'cost-of-illness' methodology for one year per patient. All costs were calculated according to payer perspective. The costs covered were pyhsician visits, hospitalizations, diagnostic tests, medicine and comorbid disease. RESULTS According to recent studies, the percentage of controlled, partially controlled and uncontrolled patients were 22%, 50%, and %28 respectively in Turkey. The cost of asthma calculation was based on weighted percentage of control. The mean annual cost per patient with controlled asthma was € 558,41, partially controlled  asthma was € 594,86 and uncontrolled asthma was € 1040,63. Hospitalizations, physician visits, diagnostic tests, comorbidity and medication costs were estimated to be 4%, 11%, 11%,  28%, 46% for controlled patient, 10%, 11%, 10%, 43%, 26% for partially controlled patient and 48%, 6%, 6%, 25%, 15% for uncontrolled patient respectively. CONCLUSIONS The cost of adult asthma in Turkey is very high and it significantly depends on disease control level. As expected, uncontrolled patient’s cost is higher than that of controlled patient. Nationwide health policies such as education of patients and physicians, selecting the right treatment and smoking cessation strategies that target  the effective control of asthma will play an important role in the reduction of the economic burden of disease.