Obstructive sleep apnea hypopnea syndrome (OSAHS) is an important medical condition which is on the increase in the past 50 years. It causes significant morbidity and mortality in both developed and developing nations of the world. To review the relevant literature on obstructive sleep apnea. Literature review was carried out on the pathophysiology, clinical presentation, complications, diagnostic modalities, and treatment using computerized search. Additional information was obtained by cross referencing and using texts and journals in the medical libraries of Federal Medical Centre Owerri and University of Nigeria, Enugu. Most of the literature was from developed countries, with very few reports from Africa. Comprehensive management plan was lacking in many textbooks. OSAHS is an increasing medical and, more importantly, respiratory condition across the world. Early recognition and prompt appropriate intervention measures will reduce the mortality and improve the quality of life in patients with such conditions.