Purpose: Irradiation in the oral cancer patients causes early and late complications such as intraoral mucositis and fibrosis, with a various expression of GM-CSF and TGF-${eta}1$. The purpose of this study was to investigate the production of GM-CSF and TGF-${eta}1$ by the irradiated human gingival fibroblasts cultivated with lipopolysaccharide. Materials and Methods: Irradiated (total dose, 60 Gy) human gingival fibroblasts were incubated with LPS. Culture supernatants that were collected at 24, 48, and 72 hours were assessed for GM-CSF and TGF-${eta}1$ by enzyme-linked immunosorbent assay. Results: 1. GM-CSF production in nomal gingival fibroblasts was increased with incubation time, but decreased with incubation time in irradiated gingival fibroblasts. GM-CSF production in both normal and irradiated gingival fibroblasts induced with LPS was higher than the control. 2. TGF-${eta}1$ production in normal gingival fibroblasts was decreased after 24 hours, but, it was increased until 48 hours in irradiated gingival fibroblasts. TGF-${eta}1$ production in normal gingival fibroblasts exposed with LPS was higher than the control. Conversely, It was lower than the control in irradiated gingival fibroblasts exposed with LPS. Conclusion: This indicates that irradiation in gingival fibroblasts may play an important role in radiation-induced intraoral mucositis and fibrosis. However, LPS decreases the production of TGF-${eta}1$ in the irradiated gingival fibroblasts.