OBJECTIVE: Common upper respiratory tract viruses are the most frequent and important causes of asthma exacerbations in both children and adults. Prospective epidemiologic studies report that up to 80% of childhood exacerbations are associated with viral upper respiratory tract infections. MATERIALS AND METHODS: The study group consisted of 104 children with asthma aged 3-17 years who received treatment for asthma exacerbations in our clinic between September 2009 and 2010. Nasopharyngeal and nasal swabs were obtained from all patients during an acute attack, and from the control group (31 subjects). These specimens were investigated for the presence of viral respiratory pathogens using a real-time multiplex PCR method. The patients were compared for the presence of respiratory pathogens and factors related to the severity of the asthma exacerbation. RESULTS: A pathogenic respiratory virus was detected in 53.8% of patients in the acute exacerbation group. The most commonly encountered viral agent was Rhinovirus (35.6%). Patients who had an acute exacerbation with or without a detectable viral pathogen were compared according to the severity of the exacerbation, the need for systemic steroids, and hospitalization rates. No statistically significant difference was found. CONCLUSION: Although viral upper respiratory tract infections are the most common cause of asthma exacerbations, the severity level of the exacerbation seems to be independent of whether a respiratory virus has been detected.