Objective and method a descriptive cross-sectional study in 90 children aged from 2 month to 2 years with acute bronchiolitis admitted to the Pediatric Departement, Hue Central Hospital from April 2010 to March 2011 was conducted to describe the epidemiological, clinical, and laboratory features of RSV and nonRSV acute bronchiolitis, and to evaluate the correlation between RDAI (Respiratory Distress Assessment Instrument) and the clinical and laboratory features. Results: The rate of RSV bronchiolitis was 23.33 percent. Most of patients were under 12 month of age. The most common symptoms were cough (100 percent), clear rhinorrhea ( 85 percent) and wheezing ( 78 percent). Fever was less common " 70 percent). The most common signs were tachypnea (84 percent), wheezes (90 percent), retractions ( 78 percent), rhonchus ( 78 percent), reduced breath sound ( 61 percent). Coarse crackles were less common ( 35 percent). RDAI score correlated negatively with ages (r