Background: Dysregulation of eicosanoids is associated with asthma and a composite of oxylipins, including exhaled LTB4, but their potential utility in monitoring the therapeutic outcomes has not been comprehensively assessed. Objectives: We aimed to examine the levels of major eicosanoids representing different metabolic pathways in exhaled breath condensates (EBCs) of children with asthma during exacerbation and after treatment. Methods: Levels of 6 exhaled eicosanoid species in asthmatic children and healthy subjects were evaluated using ELISA. Results: In addition to those previously reported, including LTB4, LTE4, LXA4 and PGE2, the levels of exhaled 15-HETE, but not TXB2, showed significant difference between asthmatics (N=318) and healthy controls (N=97). When the asthmatic population was stratified into different severity groups, the severe group was characterized by significantly lower levels of 15-HETE and 15-HETE/LTB4 ratio, as compared to the mild and control groups. Receiver Operating Characteristic (ROC) analyses revealed similar distinguishing power for the level of exhaled 15-HETE and those of FEV1 and FeNO. Analysis of asthmatics (N=75) during exacerbation and convalescence showed significant improvement in lung function (FEV1; p<0.001), but not FeNO, concomitant with significantly increased levels of 15-HETE (p<0.001) and reduced levels of TXB2 (p<0.05) after therapy, particularly for those who at the top 30% level during exacerbation. Further, decreased LTB4 and LXA4 at convalescence were noted only in those at the top 30 percentile during exacerbation. Conclusion: The exhaled 15-HETE was found to discriminate childhood asthma while decreased levels of exhaled TXB2 and increased levels of 15-HETE were prominent after treatment.