Objective:To investigate the relationship between obstructive sleep apnea syndrome (OSAS) and serum ferritin (SF). Methods:80 patients with OSAS were enrolled as subjects and 80 normal person as control Based on apnea hypopnea index(AHI),the patients were divided into mild,moderate,and severe subgroups. SF levels were measured by electrogenerated chemiluminescence. Results:The levels of SF in OSAS group were higher than those in the control group;there was a positive correlation between the level of SF and AHI. Conclusion:OSAS might be one of the causes of increased SF.