OBJECTIVES: We aimed to determine the illness severity associated with respiratory picornaviruses (rhinovirus/enterovirus). METHODS: Electronic medical records of pediatric emergency department (PED) visits were reviewed. The percent positive of respiratory pathogens, tested by using viral polymerase chain reaction panel, was determined for the July 2012 to June 2013 period. Logistic regression was used to determine the association of picornaviruses, respiratory syncytial virus (RSV), and influenza with ICU admission during the 2012-2013 academic year. Medical records of visits leading to ICU admission with picornaviruses were reviewed. RESULTS: During 2012-2013, picornaviruses were more commonly identified (22.6%) among admitted patients than influenza (6.4%) or RSV (15.1%). Picornaviruses and RSV were associated with ICU admission (picornaviruses: adjusted odds ratio [aOR], 1.99 [95% confidence interval (CI): 1.68-2.36]; RSV: aOR, 1.49 [95% CI: 1.20-1.85]) while influenza was not (aOR, 0.93 [95% CI: 0.66-1.29]). Of visits resulting in ICU admission, 79% were from patients with previous high-risk medical conditions, of which asthma or a history of wheezing was the most common (43%). CONCLUSIONS: Picornaviruses can be associated with severe disease in children, especially those with underlying medical conditions. During times of high picornavirus activity, hospitals should target infection control measures to limit the spread of picornaviruses and protect the vulnerable patients. Future research into targeted therapies for picornaviruses and vaccines is needed.