OBJECTIVE : Obstructive sleep apnea (OSA) is a complex sleep disorder associated with autonomic and sympathetic dysregulation. To the contrary, catestatin, an endogenous pleiotropic peptide cleaved from chromogranin A, is known for its inhibitory effects on catecholamine release and sympathetic activity. The aims of the study were to determine catestatin serum levels among male OSA patients compared to healthy control subjects and to explore associations of catestatin with anthropometric, polysomnographic, and lipid profile parameters. METHODS : Seventy-eight male OSA patients aged 50.3 ± 8.8 years and 51 age/sex/BMI-matched control subjects aged 50.4 ± 7.8 years were enrolled in the study. Catestatin serum levels were determined by an enzyme-linked immunosorbent assay (ELISA). RESULTS : Catestatin serum levels were significantly higher among OSA patients compared to control subjects (2.9 ± 1.2 vs. 1.5 ± 1.1 ng/mL, p < 0.001). Serum catestatin levels significantly correlated with apnea-hypopnea index (AHI) among non-obese OSA subjects (r = 0.466, p = 0.016; β = 0.448, p = 0.026), while in whole OSA population, catestatin levels significantly correlated with neck circumference (r = 0.318, p < 0.001; β = 0.384, p < 0.001) and high-density lipoprotein (HDL) cholesterol (r = - 0.320, p < 0.001; β = - 0.344, p < 0.001). In multivariate-adjusted regression model, serum catestatin was significant and independent predictor of OSA status (OR 4.98, 95% CI 2.17-11.47, p < 0.001). CONCLUSIONS : Catestatin serum levels are significantly increased in male OSA population and positively correlate with disease severity in non-obese patients. OSA status is independently predicted by catestatin levels; however, this finding is restricted to patients with moderate-to-severe disease. Further studies are necessary to elucidate the mechanistic role of catestatin in the complex pathophysiology of OSA.