ENT specialists are now being asked for help by increasing numbers of snoring patients who complain about nocturnal apnea and excessive daytime sleepiness. A final diagnosis is often made in a sleep disorders center. Sleep medicine has emerged as a new inter-disciplinary specialty during the last decade, although otorhinolaryngologists commonly are unable to fully interpret clinical findings. This report discusses the terms and information often detailed at a sleep disorders center. The evaluation of diagnostic and therapeutic procedures is explained.