Respiratory failure has been the main severe complication described in pediatric patients with influenza A H1N1 2009 (pandemic H1N1) infection. We describe the pandemic H1N1 2009 disease in children who required hospital admission and the patients' data associated with pediatric intensive care unit admission. Respiratory failure was the main complication. Extrapulmonary manifestations were also observed. Of the 127 patients, 24 required pediatric intensive care unit admission. Four patients died. Patients admitted with chronic conditions and those in whom oseltamivir was delayed more than 72 hours had a more severe disease.