Kleine-Levin syndrome (KLS) is a rare disorder characterized by periodic hypersomnia, cognitive and behavioral disturbances. Other unique symptoms in KLS are megaphagia, hypersexuality and some psychiatric disturbances such as compulsion and depression. Definite diagnosis requires the elimination of other potential etiologies. We reported a typical case of KLS in a young Thai man who suffered from seven episodes of periodic hypersomnia within 1.5 years and eventually he was diagnosed with Kleine-Levin syndrome after excluding known possible neurological conditions and sleep disorders.