In the mammalian central nervous system, nerve-glia antigen 2 (NG2) glia are considered the fourth glial population in addition to astrocytes, oligodendrocytes and microglia. The fate of NG2 glia in vivo has been carefully studied in several transgenic mouse models using the Cre/loxP strategy. There is a clear agreement that NG2 glia mainly serve as progenitors for oligodendrocytes and a subpopulation of astrocytes mainly in the ventral forebrain, whereas the existence of a neurogenic potential of NG2 glia is lack of adequate evidence. This mini review summarizes the findings from recent studies regarding the fate of NG2 glia during development. We will highlight the age-and-region-dependent heterogeneity of the NG2 glia differentiation potential. We will also discuss putative reasons for inconsistent findings in various transgenic mouse lines of previous studies.