Objective: Mesenchymal stem cells (MSCs) represent promising tools for the treatment of a wide range of disorders .In addition to their ability to differentiate into osteoblasts, adipocytes, myoblasts and neural cells, some studies have shown new light on their unique immunomodulatory properties and possible therapeutic use. Indeed, MSCs express the major kynurenine pathway (KP) enzyme, Indoleamine 2, 3-dioxygenase (IDO), in response to interferon gamma (IFN-γ), and thus can inhibit T cell proliferation and modulate immune systems. The human endometrium is a dynamic tissue. Regeneration follows parturition and extensive resection and occurs in postmenopausal women taking estrogen replacement therapy. It is likely that adult stem cells are responsible for this capacity. This study was aimed to evaluate the potential role of endometrial mesenchymal stem cells (EMSCs) on immune-suppression/ modulation. Materials and Methods: EMSC cultures were seeded into 96-well for immunocytochemistry. Subconfluent cultures were treated with different doses of recombinant human IFN-γ. The cells were rinsed and fixed with 25% glutaraldehyde and washed twice in PBS(phosphate buffer saline). Following the cells were treated with 4% bovine serum albumin (BSA) and washed. Cells were then incubated with primary antibody against IDO and then were incubated with secondary antibody and then washed with PBS. TMB and Stop solution were added and absorption was read at 450 nm. Results: Preliminary results of immunocytochemistry showed the increasing amount of IDO protein expression following IFN- γ treatment. Conclusion: Obtained results show IDO expression in INF-gamma-treated EMSCs could be subjective that may point to immunosuppressive effect of EMSCs, which need to complementary evaluations.