Drug-induced sleep endoscopy (DISE) offers an unique evaluation of the upper airway. After pharmacologic induction of unconscious sedation, it is possible to evaluate endoscopically the structures contributing to upper airway obstruction in sleep disordered breathing. The authors describe DISE techniques and the VOTE classification system for reporting of DISE findings. The VOTE classification focuses on the primary structures that contribute to upper airway obstruction and represents a common language to describe the patterns of obstruction during DISE. The latter can facilitate the scientific evaluation of DISE, including its role in directing treatment.