Since the application of electrophysiologic methods borrowed from the EEG laboratory to the study of sleeping humans, sleep disorders medicine has acquired the scientific organization necessary for its acceptance in the modern clinic. Although still in evolution, the medical science of sleep is becoming increasingly linked to the functions of the brain, carving in the territory of neurology a parcel of its own that we call neurosomnology. Patients referred to the sleep disorders specialist receive an initial evaluation that includes general medical, neurologic and when appropriate other specialized examinations. In the sleep laboratory patients undergo nocturnal and daytime polysomnography recordings which incorporate electrical brain activity, eye movements, muscle tone, EKG, limb movements, respirations, oximetry and in special circumstances penile tumescence. Scoring of the record is performed by a trained technologist and final interpretation is made by the clinical polysomnographer. The final diagnosis is discussed by the multidisciplinary team and recommendations are given at a follow-up visit by the sleep disorders specialist. Therapeutic management includes sleep hygiene, psychological support, pharmacologic treatment, ventilatory assistance and surgical interventions.