Repeated implantation failure (RIF) is a worldwide health problem that imposes a great deal of cost on patients and health care system. Vitamin D(3) has been proposed to have positive impact on the process of implantation. The present study was performed to compare the effect of 1,25-dihydroxy vitamin D(3) (1,25(OH)(2)D(3)) on cytokine production by endometrial cells of women with RIF and healthy fertile controls. Whole endometrial cells (WECs) and endometrial stromal cells (ESCs) from RIF and normal fertile women were treated with 1,25(OH)(2)D(3). The levels of IL-10, TGF-β, IFNγ, Il-6, IL-8 and IL-17 in culture supernatants were assayed by ELISA. Also, ability of the cells from both groups to produce 1,25(OH)(2)D(3) was evaluated and compared. 1,25(OH)(2)D(3) down-regulated cytokine production in WECs from both groups except for IL-8 which was upraised. Similar trends were also observed in ESCs except up-regulation of TGF-β in RIF group. Endometrial cells of both groups had comparable capacity to produce 1,25(OH)(2)D(3). Based on the minimal differential immunoregulatory effect of vitamin D(3) on endometrial cells from RIF and control women, it may be suggested that circulating levels of maternal vitamin D(3) be the subject of further investigation.