Obstructive sleep apnea (OSA) is a common condition that can cause daytime or nocturnal symptoms with long-term impact on the patient's health. Various therapies and surgeries have been introduced over the years, and patient wishes and compliance are essential factors in the success of treatment. Drug-induced sleep endoscopy (DISE) is a procedure that assesses the opening and closing of the upper airway in real time. This article summarizes the indications and contraindications of DISE, with a review of sedation methods and the VOTE classification system, in order to facilitate the use of a common nomenclature based on a protocol applied at the CHUV.