BACKGROUND: Asthma exacerbations are still a cause of hospitalization at the Emergency Department. The triggers of asthma exacerbations include allergens and infections -mostly viral-. The objective of this study was to establish the relationship between viruses detected during an asthma exacerbation and eosinophil and serum immunoglobulin E (IgE) levels in pediatric patients. POPULATION AND METHODS: Cross-sectional. analytical study. Children aged 5-15 years seen at the Pediatric Emergency Department with an asthma exacerbation in the period between March 2013 and February 2016 were included. Viral ribonucleic acid was extracted from nasopharyngeal aspirates using the CLART Pneumo Vir kit. Eosinophil levels were measured in peripheral blood and total IgE levels, in serum. Eosinophilia was defined as a count >/= 0.4 x 103/ mm3 and high IgE. as a level >/= 350 IU/L. The Pearson\'s correlation was carried out. A value of p </= 0.05 was considered significant. RESULTS: Out of 211 children with asthma exacerbation, a virus was isolated in 20%. The most commonly isolated viruses were rhinovirus. enterovirus, and respiratory syncytial virus. A correlation of 0.89 was established between eosinophil and total serum IgE levels in children with asthma exacerbation and rhinovirus, with a p value of 0.0001. CONCLUSIONS: Rhinovirus, enterovirus, and respiratory syncytial virus were the most common viruses in asthma exacerbations in children younger than 15 years. A correlation was established between eosinophil and IgE levels in the presence of rhinovirus.