Background : Humidifier disinfectant-associated lung injury (HDLI) is considered as a restrictive lung disease due to pulmonary fibrosis, which may be is characterized by decrease of DLco. Then, DLco can be a possible clinical marker of HDLI. However, there is no published information on DLco in HDLI children compared healthy controls. The purpose of this study was to evaluate the DLco in a national cohort of HDLI survivors and to compare those data to healthy controls in children. Methods : DLco were performed in a nationwide cohort of HDLI survivors aged from 5 to 12 years. To investigate reference value of DLco in healthy children, we recruited the age and sex matched outpatients who had no exposure history of HD and underlying respiratory disease. Finally, DLco in 64 children surviving the HDLI and in 151 healthy control were measured. Results : HDLI survivors had significantly lower corrected DLco (predictive %) at age 6, 8, 9, and 12 compared healthy children. (66.1% vs. 74.9%, p=0.037; 68.0% vs. 81.8%, p=0.035; 71.0% vs. 83.5%, p=0.030; 70.2% vs. 86.0%, p=0.008, respectively). Notably, both DLco and corrected DLco including predictive % and ml/min/mmHg were significantly decreased at age 12, suggesting that the difference increases with age. In age-sex matched comparison of DLco measurement between the two groups in female, corrected DLco were decreased at age 11 (73.8% vs. 90.5%, p=0.047). Also, HDLI survivors in mlaes corrected DLco had significantly lower compared controls at age 6 and 10 (8.6 ml/min/mmHg vs.9.9 , p=0.005; 69.4% vs.85.0%, p=0.059). Conclusion : The results suggested that most patients with HDLI survivors showed decrease of DLco and the mean difference between HDLI survivors and healthy children is increased as age increases, especially at age 12. DLco should be considered as a good objective markers for HDLI survivors in children. Funding : This research was supported by the Environmental Health Center for Hazardous Chemical Exposure funded by Ministry of Environment Republic of Korea (2017).