Obstructive sleep apnea (OSA), the most common form of sleep-disordered breathing, is prevalent and frequently underdiagnosed in our community. Although presenting with predominantly respiratory symptoms, the most serious complications from OSA are cardiovascular, including arrhythmias, disease of the sinus node and conducting system, and sudden cardiac death. The acute and chronic effects of OSA on the cardiovascular system, which include major effects on autonomic function during sleep and wakefulness, are potent contributors to the development and persistence of cardiac arrhythmias. Although large randomized studies are currently lacking, treatment of OSA may be an important primary or additional therapy to supplement the use of drugs or devices in the treatment of cardiac arrhythmias.