There remain controversy and disagreement on whether Oct-3/4 is expressed in neural stem cells or not. Although many reports had shown expression of Oct-3/4 in somatic stem and progenitor cells, conditional KO mice of Oct-3/4 in neural stem cells did not show any phenotype. Even pseudogenes are suspected for the "false positive" results. However, we here report that Oct-3/4 but not pseudogenes is actually expressed in neural stem cells. Western blot analysis with multiple Oct-3/4 antibodies also showed protein expression of Oct-3/4. The subnuclear localization of Oct-3/4 is clearly different from that of P19 cells, suggesting that Oct-3/4 might be inactivated by other mechanisms than transcriptional repression.