Background: Although heart rhythm disturbances may occur in sleep-disordered breathing (SDB), the prevalence of cardiac arrhythmias has been controversial. Methods: The prevalence of arrhythmias was compared in three groups based on respiratory disturbance index (RDI) of participants from Korea Health and Genomic Study (KHGS) began in 2001 as an ongoing population-based study of Korean adults aged 40 to 69 years. Among the total 5020 participants at the baseline examination, a random sample of 650 men and women was studied with employment of overnight polysomnography. Results: The overall prevalence of arrhythmias during a single night of sleep was 57.3%: sinus pause in 1.7%, 2nd degree AV block in 3.0%, atrial premature complex (APC) in 48.4%, ventricular premature complex (VPC) in 15.0%, and non-sustained atrial tachycardia (NSAT) in 2.4%. The prevalence of arrhythmias were similar between group 1 (RDI of <5) and 2 (between RDI of 5 and 30). However, APC (���5/hours) and NSAT were more common in subjects with RDI of ���30 (group 3) compared with those with RDI of <30: OR 2.92, p=0.009, OR 6.84, p=0.002, respectively. Otherwise, a significant relation was not observed in ventricular arrhythmias including VPC (���5/hours), VPC (<5/hours), bigeminy, trigeminy, and quadrigeminy. Conclusion: Our results demonstrated a significant increase in the prevalence of atrial arrhythmias, NSAT and frequent APC, among subjects who had severe SDB than those who did not. However, ventricular arrhythmias were not related to SDB in population-based sample.