Background: The global prevalence of asthma ranges from from1% to 18% of the population with significant differences among countries (about 300 million affected persons globally). YKL-40 (chitinase 3-like protein 1) is a glycopeptide produced and secreted from different cells including epithelial and smooth muscle cells of airways. It has been involved in inflammation and tissue remodeling, and increased expression of YKL-40 in diseases with T-helper-2 inflammation e.g. asthma. Objective: To evaluate the serum levels of YKL-40 in a group of Egyptian asthmatic children (both stable and acute) and compare them to a matched healthy control group. Method: This case-control study was conducted at Minia university hospitals, it was held from January 2017 to May 2017, sixty patients were included as cases which were divided into 2 subgroups: 30 acute asthmatics and 30 stable asthmatics in addition to 30 healthy age-matched children were included as controls. They were recruited from the follow-up clinics of the hospital after consent from their caregivers. Detailed history and complete physical examination were done to all children. A complete blood count was performed and estimation of serum YKL-40 level was performed using a commercial enzyme-linked immune sorbent assay (ELISA) kit. Results: YKL-40 Serum levels are significantly higher in children with bronchial asthma compared to healthy controls. Acute asthmatic children serum levels of YKL-40 are significantly higher in comparison to stable asthmatics. Conclusion: The study concludes that YKL-40 might have a role in pediatric asthma pathogenesis; however, further research on a larger scale is warranted.