A 70-year old woman was admitted because of sleep maintenance insomnia with severe respiratory sounds during sleep. Polysomnography (PSG) revealed frequent respiratory events, particularly hypopneas, throughout the night associated with severe oxygen desaturation, and inspiratory stridor, which was shown to have a high-pitched frequency by acoustic sound analysis. She also presented fine finger tremor due to parkisonism, increased bilateral tendon responses, cerebellar ataxic gait, and dysautonomia. Therefore, we concluded that she suffered from multiple systemic atrophy (MSA). Nasal continuous positive airway pressure (nCPAP) treatment was successful. Characteristic PSG findings and analysing the snoring sound are important in the early diagnosis of sleep-related disordered breathing in MSA.