We present the case of an aviator with Kleine Levin syndrome (KLS). History, physical examination, and special studies presented confirm the diagnosis of this syndrome. Our patient presented as an atypical case of KLS with respect to the presenting symptoms and to frequency of the episodes (6 years apart). He exhibited only intense somnolence, easy arousability, photophobia, hyperacousis, and a voracious appetite. Following a complete medical work up we recommended that an applicant with such a classical case of KLS be disqualified as a crewmember; however, in cases such as that presented above a limited waiver may be considered. The aeromedical significance of this case is to reinforce the importance of screening candidates and seeking precise diagnosis of a past illness or hospitalization.