As our understanding of sleep medicine grows, so does our obligation to protect patients and society from the potential harms of sleep disorders. Harm to self and others can take the form of violent behaviors during sleep or from sleep arousals, or from errors in judgment and motor skills due to excessive daytime sleepiness. Motor vehicle accidents and industrial accidents represent the majority of deaths and injuries due to sleep disorders. Errors in judgment and mental capacity can also lead to significant problems in terms of financial costs to businesses, inefficiencies in the workplace, and harm to others (as in the case of medical errors). Sleepiness can be so debilitating to an individual that he or she may qualify for disability compensation. The sleep specialist plays three basic roles in the interaction between the medical and legal fields: the educator, the medical examiner, and the expert witness. The education of the public, court officials, and patients is necessary to increase awareness of sleep disorders and their risks. The medical examination of the patient and subsequent treatment of the sleep disorder can help to minimize the risks of sleep disorders. Finally, if necessary, the sleep specialist may be called upon to provide expert testimony about the medical evidence provided and the likelihood that a sleep disorder contributed to an alleged criminal act.