These clinical guidelines from the American Sleep Disorders Association provide recommendations for when polysomnography and related sleep studies are indicated in the diagnosis of various sleep disorders. The guidelines were developed by a task force that reviewed literature on the topic and consulted specialists. Key indications for polysomnography include diagnosing sleep-related breathing disorders, assessing positive airway pressure titration, and evaluating violent or injurious parasomnias. The guidelines also provide recommendations for when polysomnography may be indicated or is not routinely needed. The goal is to help ensure appropriate and cost-effective use of sleep testing procedures.