Asthma is a common chronic condition that places substantial burden on patients and healthcare services. Despite the standards of asthma control that international guidelines recommend should be achieved, many patients continue to suffer sub-optimal control of symptoms and experience exacerbations (acute asthma attacks). In addition to being associated with reduced quality of life, asthma exacerbations are a key cost driver in asthma management. Routine clinical practice for the management of asthma exacerbations varies in different healthcare systems, so healthcare providers require local costs to be able to assess the value of therapies that reduce the frequency and severity of exacerbations. This prospective study, conducted in a total of 15 countries, assessed the local cost of asthma exacerbations managed in either primary or secondary care. Healthcare resources used were costed using actual values appropriate to each country in local currency and in Euros. Results are presented for exacerbations managed in primary care in Brazil, Bulgaria, Croatia, Czech Republic, Hungary, Poland, Russia, Slovakia, Slovenia, Spain and Ukraine, and in secondary care in Croatia, Denmark, Ireland, Latvia, Norway, Poland, Russia, Slovakia, Slovenia and Spain. Multiple regression analysis of the 2052 exacerbations included in the economic analysis showed that the cost of exacerbations was significantly affected by country (P<0.0001). Mean costs were significantly higher in secondary care (euro 1349) than primary care (euro 445, P=0.0003). Age was a significant variable (P=0.0002), though the effect showed an interaction with care type (P<0.0001). As severity of exacerbation increased, so did secondary care costs, though primary care costs remained essentially constant. In conclusion, the study showed that asthma exacerbations are costly to manage, suggesting that therapies able to increase asthma control and reduce the frequency or severity of exacerbations may bring economic benefits, as well as improved quality of life.