The purpose of the current study is to compare the effect of nebulized 3% hypertonic saline in treatment of bronchiolitis with nebulized 0.9% normal saline in 2-24 month children. In a non-randomized controlled trial during two falls and two winters from 2008-2010, the study population was all 2-24 month children with diagnosis of acute bronchiolitis referring to Ali-e-Asghar Pediatric center. Inclusion criteria were: first or second episode of respiratory distress with wheezing and clinical manifestation of viral infection e.g. temperature >= 38 degree of centigrade, respiratory rate >=100, pulse rate >= 180 or coryza. Exclusion criteria were: chronic respiratory or cardiac disease, immunodeficiency, Down syndrome, Metabolic or neurologic disorders, history of prematurity (gestational age < 34 wks), mechanical ventilation in neonatal period, family history of asthma and toxic patient requiring urgent admission due to dehydration, decreased level of consciousness, lethargy and sign of respiratory failure. Each patient participated one time in the study. Sixty patients entered consecutively into the study. Thirty patients received nebulized 3% hypertonic saline as treatment group and 30 patients received nebulized 0.9% normal saline. Primary outcome were change in sum of RADI score and Yale clinical score and admission rate. Secondary outcome were duration length of hospital stay, intravenous fluid use, need to O2 therapy and remission of cough and wheezing.