Mesenchymal stem cells isolated from human endometrium (eMSC) are perspective source of stem cells for regenerative medicine. Large amount of these cells accumulated by in vitro cultivation is usually required for transplantation into patients. We established several cell eMSC lines and cultivated them during long period of time to examine the possibility of their spontaneous transformation. All cell lines demonstrate limited lifespan, undergo replicative senescence and die. Karyotypic analysis on different passages reveals that most cells display karyotypic stability. Thus, extended in vitro cultivation of eMSCs does not lead to spontaneous transformation that makes therapeutic application of these cells safety for patients. During long-term cultivation eMSCs sustain the expression of surface markers.