Stem cells are capable of self-renewal and differentiation into a wide range of cell types with multiple clinical and therapeutic applications. Stem cells are providing hope for many diseases that currently lack effective therapeutic methods, including stroke, amyotrophic lateral sclerosis, Alzheimer's disease, and Parkinson's disease. Embryonic stem (ES) cells were originally targeted for differentiation into functional dopamine neurons for cell therapy. Today, induced pluripotent stem (iPS) cells are being tested for such purposes as generating functional dopamine neurons and treating a rat model of Parkinson's disease. In addition, neural stem cell and mesenchymal stem cells are also being used in neurodegenerative disorder therapies for stroke and Parkinson's disease. Although stem cell therapy is still in its infancy, it will likely become a powerful tool for many diseases that currently do not have effective therapeutic approaches. In this article, we discuss current research on the potential application of neural stem cells, mesenchymal stem cells, ES cells, and iPS cells to neurodegenerative disorders.