In patients with multiple system atrophy (MSA), sleep related breathing disorders (SRBD), including obstructive and central sleep apnea, vocal cord abductor paralysis and dysrhythmic breathing pattern, are frequently observed. SRBD may have a considerable impact on variation of autonomic nervous activity during sleep. The previous studies correlated upper airway muscle dysfunction related parkinsonism with increased prevalence of SRBD in patients with Parkinson's disease (PD). However, recently, the clinical significance of SRBD and its impact on sleepiness and disease severity have been debated. In this review, we discuss sleep and autonomic function, especially, SRBD in PD and related disorders, including the previous studies from our department.