Abstract: Objective: To observe the value of B-type natriuretic peptide(BNP) in differentiating cardiac dyspnea from lung diseases in children.Methods: The concentrations of BNP in 24 children with congestive heart failure(CHF),23 with pneumonia,18 with CHF combined with pneumonia and 15 healthy children were measured with BNP ELISA KIT.Results: The BNP level of the patients with CHF was(141.55±75.99)pg/ml,which was significantly higher than that of patients with pneumonia(26.00±14.57)pg/ml(P<(0.01)) and higher than that of patients with CHF combined with pneumonia(113.73±87.05)pg/ml(P<0.01),and higher than that of healthy children(19.31±10.29)pg/ml(P<0.01).The BNP level of the patients with CHF combined with pneumonia was significantly higher than that of patients with pneumonia and that of healthy children(P<0.01).The BNP level was not significantly different between the latter two groups(P>0.05).Conclusions: It suggests that the level of BNP is of value in determining the cardiac function of children with pneumonia.