The concept that everything can die, but nothing can regenerate in the brain has been replaced with new hope that stem cells will provide avenues to repair the damaged central nervous system (CNS). The treatment of brain damage has been demonstrated preclinically using a variety of stem cell sources. The prototypical cell that gives rise to the CNS is the neural stem cell (NSC). NSCs differentiate into site-appropriate phenotypes when transplanted into the damage brain and can recover lost functions. In some cases, cells can be pre-differentiated into a particular neuronal phenotype, such as dopaminergic cells, that can then be transplanted ectopically to promote behavioural improvements in conditions like Parkinson's disease. Early clinical studies in PD have demonstrated the proof of principle that this approach can improve neurodegenerative disease. The current review will discuss the different sources of stem cells in their preclinical and clinical application, as well as providing an overview as to the issues that need to be addressed to ensure a successful translation from bench to bedside.