Mineral trioxide aggregate (MTA) would influence healing of periapical tissues by modulating the production of growth factors and cytokines from PDL fibroblasts, however, the studies are insufficient. Therefore, the purpose of this study was to monitor the expression of transforming growth factor-beta1 (TGF-β1), fibroblast growth factor-2 (FGF-2), and interleukin-6 (IL-6) from PDL fibroblasts in the presence of MTA. The human PDL fibroblasts were seeded onto the set MTA or IRM at a level of 1 × 10⁵ cells per unit well, and further incubated for 6, 12, 24, and 48 hours. The levels of TGF-β1, FGF-2, and IL-6 from the supernatant were measured by enzyme-linked immunosorbent assay (ELISA). The data were analyzed using one-way ANOVA. The level of TGF-β1 was down-regulated when the cells were grown in the presence of MTA except at 6 hours. The levels of FGF-2 release were significantly suppressed when PDL fibroblasts were grown in the presence of MTA or IRM at all time intervals (p < 0.05). The expressions of IL-6 from MTA treated cells were comparable to those of untreated control cells throughout the observation periods. We presume that this material inhibits the stimulatory function of growth factors on granulation tissue formation and in turn, it promotes the healing process modulated by other bone-remodeling cells.