There is currently no effective treatment for some motor neuron diseases, such as spinal muscular atrophy and amyotrophic lateral sclerosis. With the development of induced pluripotent stem cells and cell reprogramming technology, it is possible to induce the production of motor neurons from a patient’s somatic cells in vitro for autologous transplantation. The differentiated motor neurons can also be used as cell models for studying disease mechanisms and for drug screening. Many researchers are now focusing on the differentiation of motor neurons from fibroblasts in vitro; here, we summarize three different methods for this, namely, differentiation through induced pluripotent stem cells, neural stem cells, and direct conversion.