Obstructive sleep apnea (OSA) is an increasingly common sleep disorder, which is of particular concern to anesthiologists because it is associated with increased perioperative morbidity and mortality. Because OSA is undiagnosed in an estimated 80 percent of patients, it is necessary that anesthesia practitioners have adequate knowledge of the clinical presentation and diagnosis of OSA. OSA has many predisposing factors, the most common and suspected factors are obesity, body fat distribution, smoking, nasal obstruction, laryngeal obstruction, endocrine/metabolic and neuromuscular disorders. There are many sequelae of OSA, the most important and threatening of them are cardiovascular (e.g., hypertension, ischaemic heart disease, right heart failure) and pulmonary sequelae (e.g., hypoxaemia, hypercapnea, pulmonary hypertension). Patients with OSA are at a high risk of perioprative complications and pose several challenges to anesthiologists including difficult tracheal intubation and increased postoperative complications (e.g., respiratory obstruction after extubation or respiratory depression after opioid administration). The key to safe anesthetic care for these patients is a careful and meticulous preparation which begins with thorough preoperative assessment, a thoughtful and well executed anesthetic plan and extends well into the postoperative period.