OBJECTIVE: To study the viral etiology of acute respiratory infection (ARI)in children from Wenzhou, Zhejiang between 2007 and 2008. METHODS: The nasopharyngeal aspirate samples were obtained from 5 097 hospitalized children with ARI. Seven common respiratory viruses, including respiratory syncytial virus (RSV), influenza virus A and B, parainfluenza viruses 1, 2 and 3 and adenovirus, were detected using direct immunofluorescence. RESULTS: Viral agents were identified in 2 209 cases (43.3%).Of the 2 209, RSV was the most frequent (78.1%), followed by parainfluenza 3 (12.4%), influenza virus A (3.0%), adenovirus (2.8%), parainfluenza 1 (1.7%), influenza B (0.5%) and parainfluenza 2 (0.3%). The infants at ages of <3 months and <6 months had higher detection rate of viruses (53.6% and 49.2%, respectively). A highest detection rate of viruses was found in winter. CONCLUSIONS: RSV is the leading pathogen of ARI in children from Wenzhou, Zhejiang between 2007 and 2008. The children at age of less than 6 months are susceptible to respiratory viruses. The viral activity peaks in winter.［Chin J Contemp Pediatr, 2010, 12 (1):32-34］