Following the completion of the Human Genome Project, a lot of progress has been made in understanding the genetic basis of motor neuron diseases (MNDs) and neuropathies. Spinal Muscular Atrophies (SMA) are caused by mutations in the SMN1 gene localized on Chromosome 5q11. Amyotrophic Lateral Sclerosis (ALS) has been found to have at least 18 different types, many of them associated to different genetic loci (e.g. SOD1, ALS2, SETX, FUS, VAPB, ANG, TARDBP and others), but many of the forms have still not been associated with a particular gene. Sensomotoric hereditary neuropathies (Charcot-Marie-Tooth) are a large heterogeneous group of various hereditary neuropathies, which have also been associated with a wide spectrum of genetic mutations, such as PMP22, LITAF, EGR2, P0 protein, KIF1B, MFN2, RAB7 and others. It is also apparent that more genes are being implicated, mutations discovered, and phenotypes recognised and broadened. Therefore, a lot of continuing, additional research effort will be required in the coming years to illuminate pathogenic mechanisms that underlie motor neuron diseases and neuropathies and that could lead to new and improved treatments.