Abstract: The invention relates to highly proliferative stem cell obtained from menstrual fluid. The menstrual stern cells (MenSCs) may be cultured in vitro and exhibit mesenchymal stem cell (MSC)-like properties and some culture and expansion advantages. This population of MenSCs, compared to the broadly studied bone marrow derived stem cells (BM-MSCs) out-performs bone marrow derived mesenchymal stem cells in proliferation rate and support of hematopoietic stem cell (HSC) expansion in vitro. MenSCs demonstrate to maintain their stem cell properties over 2 years, being genetically stable, without expressing surface differentiation markers, and they also show the ability to differentiate into adipocytes, chondrocytes and osteoblast cells. MenSCs can be easily and periodically obtained, isolated and cultured.