To describe the clinical and economic burden of severe asthma in France over 12 months. Data were retrieved from the observational, prospective “Cohorte Obstruction Bronchique et Asthme” (COBRA) cohort, which has enrolled nearly 1000 asthma patients since 2007 from throughout France. Patients undergoing treatment with GINA step-4 or 5 medications uninterruptedly for 12 months (thus defining “severe asthma”) were identified and their clinical data used to describe the clinical burden of asthma (exacerbations, symptoms outside exacerbations, and level of asthma control). Patients’ utilization of healthcare resources was described and used to estimate the direct medical costs incurred to treat severe asthma. 155 patients were included in the present study. Over the 12-month period of interest, 128 (83%) patients experienced at least one asthma exacerbation, 22 (14%) patients were hospitalized for asthma, 133 (86%) patients experienced continuous symptoms outside exacerbations, and 77 (50%) patients experienced important limitations in daily life activities. The median number of asthma-related drugs used was 4. The mean estimated annual asthma-related cost was 8,222 euros (standard deviation, SD = 11,886), including 7,229 euros (SD = 11,703) for controller medications. Symptoms outside exacerbation periods are highly prevalent in severe asthma patients, for whom the main driver of medical costs is controller medication. •In severe asthma, asthma symptoms occurring outside exacerbation periods are as frequent in patients with exacerbations than in patients without exacerbations.•The main driver of direct medical cost is asthma controller medication.