Objective: Human adipose tissue is known to be an attractive and readily available source of mesenchymal stem cells (MSC). Further clinical interest has been increased by the observation that MSC display immunomodulatory capacities. Most of the protocols, currently used for in vitro expansion of MSC, include fetal bovine serum (FBS) supplementation. MSC cultured in such a way for clinical applications rise the concerns about immunogenicity of FBS proteins. A possible solution to this problem is the use of autologous serum (AS) instead of FBS. This study investigated whether adipose-derived stem cells (ADSC), cultivated in the medium containing AS, maintain characteristics and immunomodulatory properties of MSC. Materials and Methods: Abdominal adipose tissue from the 40 year old man was used to isolate ADSC that were cultivated and propagated in a medium supplemented with the 5% autologous serum (10% of AS for first 10 days ). Characteristics of MSC were demonstrated by immunocytochemistry and differentiation of ADSC followed by specific staining with Oil Red O, Alizarin Red S and Alcian Blue. Immunomodulatory properties of ADSC were investigated by blast transformation reaction using donor’s peripheral blood mononuclear cells (PBMNC). Results: Obtained ADSC were plastic adherent, rapidly dividing (doubling time 40 ± 4 hours) spindle-shaped cells with fibroblastoid morphology, normal 46, XY karyotype and telomere length of 16,8 kilobases. Immunocytochemical analysis showed that obtained cells express typical MSC surface markers: CD73, CD90 and CD105 and lack expression of hematopoietic markers such as CD34 and CD45. ADSC underwent in vitro differentiation into adipocytes, osteoblasts and chondroblasts, confirmed by Oil Red O, Alizarin Red S and Alcian Blue stains respectively. Addition of ADSC to PBMNC induced suppression of T lymphocyte proliferation. Significant immunosuppressive properties of ADSC were observed at ratio 1:10 and 1:1 (ADSC:PBMNC) with the most prominent effect at the latter proportion. Conclusion: Our results indicate that ADSC can be effectively cultured and expanded in the presence of AS. Such culture conditions do not influence the expression of characteristic MSC markers, ability to differentiate into adipocytes, osteoblasts and chondroblasts and immunosuppressive properties of ADSC. The use of AS instead of FBS make cultivation of MSC for therapeutic use possible without the risks of xenogeneic immune responses caused by animal proteins.