This chapter reviews the nocturnal sleep disorders associated with Parkinson's disease (PD). The most common sleep disorders in PD include insomnia, REM sleep behavior disorder (RBD), sleep apnea, restless legs syndrome (RLS), and periodic limb movement disorder (PLMD). The diagnosis of RLS in PD patients may be confounded by akathisia and nocturnal motor symptoms. The presence of diurnal variations of symptoms in RLS, and the feeling of inner restlessness without a sensory component in akathisia, may help to differentiate akathisia from RLS. The primary neurodegenerative process of PD, complex medication regimens, age-related changes in the sleep architecture, and co-existent sleep disturbances play an important role in the development of excessive daytime somnolence (EDS). Several objective and subjective diagnostic tools have been used for the diagnosis of EDS in PD patients. Deep brain stimulation (DBS) has become an important treatment option for PD patients with disabling motor complications and dyskinesias.