Multilineage-differentiating stress enduring (Muse) cells are nontumorigenic endogenous pluripotent-like stem cells easily collected from various adult or fetal tissues. The tissue regenerative effects of Muse cells have been demonstrated in many disease models, as they reach damaged sites after intravenous injection to exert pleiotropic effects. Previous reports indicate that several human tissues are readily accessible for Muse cell isolation, including adult tissues such as bone marrow (BM) and embryonic tissues such as Wharton’s Jelly (WJ) from umbilical cord. Wa analyzed the protein repertoires of WJ-Muse and BM-Muse using mass spectrometry-based proteomics.