Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder characterized by repeated episodes of obstructed (apnea) or reduced (hypopnea) airflow in the upper airway during sleep. Obstructive sleep apnea results in variable arterial oxygen desaturations and arousals leading to sleep fragmentation. Most patients with OSA first come to the attention of a clinician when they complain of daytime sleepiness or when their bed partner reports loud snoring and witnessed episodes. Obstructive sleep apnea is associated with impaired quality of life, cardiovascular disease, metabolic syndrome, and motor vehicle accidents, yet the disorder remains undiagnosed in a significant portion of the population. Overnight polysomnography, whether facility-based or portable, is required for appropriate patient diagnosis. Portable monitoring can be used in patients with a high pre-test probability for moderate-to-severe OSA, who are without significant comorbidities. Management of OSA requires a long-term multidisciplinary approach. Continuous positive airway pressure (CPAP) remains the mainstay of treatment for patients with moderate-to-severe OSA. Oral appliances may be indicated in patients with mild-to-moderate OSA who do not wish to use CPAP. Surgical therapy is generally reserved for selected patients in whom CPAP or oral appliance are not an option.