Background: A number of previous works have shown that leukotriene (LT) concentration emerged disease severity-dependent increases in both exhaled breath condensate and urine of sleep-disordered breathing (SOB) patients. However, few studies have investigated how circulating level of LTs contributes to systemic inflammation of SDB, and the relationship between LT production, leukocyte count and high sensitivity C-reactive protein (hsCRP) level in SDB disease remains controversial. Methods: Prospective, observational study that included standard questionnaires, physical examinations and polysomnography. Serum leukotriene B-4 (LTB4) and cysteinyl leukotrienes (cysLTs) were determined by means of enzyme-linked immunosorbent assays. Results: A total of 166 children with SOB and 45 control subjects were recruited. SOB children had increased serum levels for both LTB4 and cysLTs as well as neutrophil (Neu) count and hsCRP than the control group, and all the inflammatory parameters emerged disease severity-dependent increases. LT production correlated significantly with Neu count and hsCRP level. In the regression model, both apnea-hypopnea index and body mass index z-score were significant predictors of LTB4 and cysLTs (p < 0.001). Conclusions: The activated systemic inflammatory response as reflected by serum elevations of LTs, Neu counts and hsCRP is present in children with SDB, and the magnitude of inflammation emerged disease severity-dependent. The level of LTs is significantly associated with circulating Neu counts and hsCRP values in SOB. (C) 2014 Elsevier B.V. All rights reserved.