Abstract: 　Objectives　To investigate the clinical significance of the airway inflammation mediators， eosinophil cationic protein (ECP) and urinary leukotriene E4 (LTE4)， in children with respiratory syncytial virus (RSV) bronchiolitis. Methods A total of 120 inpatients with RSV bronchiolitis were classified into atopic and non-atopic groups. And 30 healthy subjects were selected as normal controls. Urinary LTE4 was determined by ELISA and ECP concentration in nasopharyngeal secretions (NPS) was tested by UniCAP100 allergen detector. The differences among groups were compared. Results The urinary LTE4 level in atopic group (172.21±67.29 pg/ml) was elevated significantly (P<0.01) than that of non-atopic group (78.21±28.78 pg/ml) and control group (44.22±16.14pg/ml). Significance was also found between non-atopic and control groups (P<0.01). Statistical analysis indicated that urinary LTE4 positively correlated to serum IgE and ECP in children with RSV bronchiolitis (r=0.57，0.49; P<0.01). Conclusions The level of urinary LTE4 and ECP in NPS can provide the reference for treatment and prognosis of children with RSV bronchiolitis. #br#Key words：　respiratory syncytial virus;　bronchiolitis;　leukotrienes;　eosinophil cationic protein;　children#br#