We describe an obese child with severe obstructive sleep apnea syndrome in whom nocturnal frontal lobe seizures developed within a week after therapy was started with continuous positive airway pressure. The video polysomnographic study after the onset of nocturnal episodes showed 3 seizures: 2 starting from slow-wave sleep when he was sleeping with continuous positive airway pressure, and 1 from stage 2 non-rapid eye movement sleep when he was sleeping without continuous positive airway pressure. Cyclic alternating pattern analysis during the video polysomnography recorded after the onset of nocturnal seizures disclosed a high cyclic alternating pattern rate during slow-wave sleep, and the recording obtained after antiepileptic therapy began showed a low cyclic pattern analysis rate. In this child, we describe the non-rapid eye movement sleep instability induced by continuous positive airway pressure therapy might have had a role in triggering the nocturnal seizures.