Parkinson's disease (PD) is a common and incurable neurodegenerative disease, affecting 1% of the population over the age of 65. Although the disease remains defined clinically by its cardinal motor manifestations and pathologically by substantia nigra neuronal loss in association with intraneuronal Lewy bodies, the molecular mechanisms that lead to neurodegeneration remains elusive. It is becoming increasingly clear that genetic factors contribute to its complex pathogenesis. More than 23 loci and 13 genes, including LRRK2, SNCA, GBA1, PRKN, PINK1, and PARK7/DJ-1 clearly linked to inherited forms of Parkinsonism have been identified to date. The knowledge acquired from their protein products has revealed pathways of neurodegeneration that can be shared by Mendelian and sporadic Parkinsonism, including synaptic, lysosomal, mitochondrial and immune-mediated mechanisms of pathogenesis. This special issue "Parkinson's Disease: Genetics and Pathogenesis" collects 12 high-quality papers, including seven original research articles, and five reviews, that seeks to deepen the knowledge of multiple aspects related to Parkinsonism.