Stem cells are self-renewable and multipotent, and exist in various tissues including fetal brains. There is a growing knowledge of how stem cells differentiate into mature cells and how the niche, a microenvironment surrounding stem cells, regulates their proliferation and differentiation. Consequently, establishment of a cell replacement therapy to treat many neurological disorders that are presently incurable is strongly anticipated. In this report, we present a survey of experimental trials of treatment using neural stem cells in animal models of various neurological disorders such as Parkinson’s disease (PD), multiple sclerosis, stroke, spinal cord injury, and perinatal hypoxia-ischemia. In some of these trials, neural stem cells were transplanted in combination with modulation of the extracellular matrix of host tissues. Although many problems remain to be solved in advance of clinical use, stem cell transplantation combined with niche modulation could be a novel strategy for treatment of various neurological disorders.