Kleine-Levin syndrome is an uncommon disorder with recurrent episodes of hypersomnia, and behavioral abnormalities such as binge-eating and hypersexuality. Our aims were to report cases of the Kleine-Levin syndrome diagnosed in Buenos Aires, Argentina and to characterize the clinical presentation of these patients. We evaluated patients with Kleine-Levin syndrome according to the International Classification of Sleep Disorders. Psychiatric, physical and neurological symptoms were present. Some patients were investigated with brain Magnetic Resonance Imaging, Single Photon Emission Computed Tomography, electroencephalogram and some with polysomnography. Seven patients (2 female, 5 male), ages from 8 to 47 years (median 20.7 years) were included in the study. The duration of symptoms was 1.5-20 days with a mean of 8. The range of interval between episodes: 2.5-24 months, median=13. All seven patients had a history of hypersomnia (one of them post head injury); 5 reported hyperphagia and 2 reduced appetite. Brain MRI was performed in 6 patients: 1 showed non-specific abnormalities and another presented diencephalic hematoma; the rest were normal. Our paper is the first one in Buenos Aires reporting Kleine-Levin syndrome of different ethiologies. The prevalence is difficult to estimate in our country.