Since the role of cord blood (CB) regulatory T cells (Tregs) for the suppression of the allogeneic T-cell response is under investigation, we analyzed and compared the functional properties and gene expression profile of Tregs expanded from CB units or from the peripheral blood (PB) of helathy donors. Tregs were purified from 23 CB units and from the PB of 13 donors and expanded for 6 days with anti-CD3, anti-CD28 and IL-2. Immunophenotypic analyses were performed, and suppressor activity of expanded Tregs was measured in mixed lymphocyte reaction (MLR) cultures. The IL-10 production capacity was tested and gene expression profile experiments were performed on 6 Tregs from PB and 4 from CB. CB and PB Tregs had similar immunophenotypic features. Tregs from CB presented a higher expansion capacity and genomic characterization showed in CB-derived Tregs a significant enrichments of genes involved in cell proliferation, chromatin modification and regulation of gene expression in CB-derived Tregs. All samples were positive for the Foxp3 gene and protein after expansion. CB and PB expanded Tregs exerted a comparable and potent suppressive function of MLR and presented a high in vitro IL-10 production capacity. Gene profile analysis also revealed for PB Tregs a significant enrichments of genes involved in the adaptive immune response.