The aim of this review is to provide an update on the relationship between sleep and neurodegenerative disorders. The knowledge about REM behavior disorder has increases a lot in the last decades. The relationship is well established with α-synucleinopathies (Parkinson’s disease, multiple system atrophy (MSA) and Lewy body dementia) which, in some cases, makes up the prodromic stage. Restless legs syndrome and the periodic limb movements of sleep are related to some of these disorders. Particularly, the laryngeal stridor and its probability of sudden death during sleep should be taken into account in MSA, more so since there is an effective treatment with CPAP. At the end of this paper, we have some words about the sleep in choreas, the influence of circadian rhythms in Alzheimer’s disease, and fatal familial insomnia.