Abstract: Brain injuries like ischemic stroke induce endogenous stem cell production. Although the precise traits of stem cells in pathological brains remain unclear, we previously demonstrated that injury/ischemia-induced stem cells (iSCs) are present in the post-stroke mouse (Nakagomi et al., 2009) and human brains (Beppu et al., 2019). Additionally, we demonstrated that not only mouse-derived (Nakagomi et al., 2009) but also human-derived iSCs (Beppu et al., 2019) produce electrophysiological functional neurons in vitro. Further, we recently demonstrated that transplantation of human-derived iSCs into poststroke mice improves neurological function, presumably by neural replacement and the formation of neural networks with endogenous neurons (Nakagomi et al., 2023). Thus, iSCs may play an important role in neural regeneration after brain injuries, such as ischemic stroke. Herein, we introduce the concept, origin, traits, and roles of iSCs and their future perspectives based on our recent findings.