Obstructive sleep apnea syndrome (OSAS) has been associated with motor vehicle accidents and work-related injuries. Proposed mechanisms for this association have included excessive sleepiness, decreased vigilance, inattentiveness, and psychological impairment, all related to the abnormal sleep and nocturnal hypoxia seen in OSAS. This report describes a case of an accidental gunshot wound to the head in an individual with known OSAS who was experiencing progressive cognitive and psychological deterioration due to suboptimal treatment of his sleep-disordered breathing. The literature on the neuropsychological consequences of OSAS is briefly reviewed.