A recent study has reported that pluripotent stem cells can be categorized according to their pluripotent state. The first is a “naïve” state, which is characterized by small, round or dome-shaped colony morphologies, LIF and BMP4 signaling pathways and two active X chromosomes in female; mouse ES cells (mESCs) represent this type. A second “primed” state has also been described and is possible in mouse epiblast stem cells (mEpiSCs) or human ES cells (hESCs). These primed state pluripotent stem cells display flattened monolayer colony morphologies, FGF and Nodal/Activin signaling pathways and X chromosome inactivation in female. It has been suggested that, as a non-permissive species, the porcine species undergoes reprogramming into a primed state during the establishment of pluripotent stem cell lines. Meanwhile, a few studies have reported that primed pluripotent stem cell lines could be reverted to a naïve pluripotent state using various exogenous factors including GSK3β and MEK inhibitors, LIF, hypoxic conditions and up-regulation of Oct3 or klf4. Therefore, the purpose of this study was to investigate whether a LIF-dependent naïve pluripotent stem cell line could be derived from porcine embryonic fibroblasts(PEFs) via doxycycline (dox)-inducible reprogramming factors and LIF. In this study, we have been able to successfully induce PEFs into a LIF-dependent naïve pluripotent-like cell line showing a mESC-like morphology and the expression of pluripotent markers. Our results suggest the possibility of reprogramming to naive pluripotent- like stem cells from PEFs in porcine species. * This work was supported by the BioGreen 21 Program (PJ0081382011), Rural Development Administration, Republic of Korea.