The effects of Platelet-derived growth factor-BB(PDGF-BB) and Basic-fibroblast growth factor (b-FGF) on the proliferation and production of hyaluronic acid and, cytokine productions in cultured human orbital fibroblasts were evaluated. Orbital fibroblasts were cultured (5 from eyes with thyroid-associated ophthalmopathy and, 5 from normal eyes) and classified into 3 groups-: (1) the Unstimulated group, (2) the Platelet-derived growth factor-BB stimulation group and, (3) the b-Fibroblast growth factor stimulation group. The hyaluronic acid concentration of each group was measured by ELISA. The cytokine production (IL-$1{eta}$, IL-2, IL-6, IL-8 and RANTES) of each group was measured in the cultured medium. The proliferation of orbital fibroblasts was measured in each group using a thymidine analog EdU, which can be incorporated into DNA during active DNA synthesis. In conclusion, PDGF-BB and b-FGF induced orbital fibroblasts increased production of hyaluronic acid in thyroid-associated ophthalmopathy. In addition to the induction of orbital fibroblast proliferation, PDGF-BB increased the production of IL-8. Further studies on the inhibitory factors of orbital fibroblasts with a larger sample size are warranted to aid in the development of fundamental treatments for thyroid-associated ophthalmopathy.