Ko, Lim found some differences in the concentrations of bone resorptive cytokines, especially IL-$1{alpha}$ and IL-$1{eta}$ in periapical lesions and inflamed pulps. And they suppose that these differences may be due to the type of cells which produce each cytokine. The purpose of this study was to analyze the human odontogenic cysts & cystic fluid for their contents of IL-$1{alpha}$, IL-$1{eta}$ and TNF-$1{alpha}$ and to compare the concentrations of each cytokine according to the cytokine producing cells. The cystic tissues used in this experiment, were obtained from periapical surgery or cyst enucleation surgery. Cystic fluid was obtained from root canal during routine endodontic therapy(n=5). Cystic tissues were subdivided into two groups, inflammatory radicular cyst group(n=15) and developmental odontogenic keratocyst group(n=3). Normal periapical tissues of extracted third molar(n=5) were also obtained to be used as control group. Each specimen was incubated in 0.5ml homogenizing buffer (0.1mol/L potassium chloride, 0.02mol/L TRIS;pH=7.6) for two hours and then homogenized with glass homogenizer. Each specimen was centrifuged in a microcentrifuge for 3 minutes, and supernatants were extracted. The concentrations of cytokines were measured with R&D ELISA kit. The data were analyzed by Mann-Whitney U test for the differences among the diseases and t test for the correlations among each cytokine. Following results were obtained ; 1. For IL-$1{alpha}$ and IL-$1{eta}$, all experimental groups showed significantly higher concentrations of each cytokine than the control group (p<0.05). 2. In radicular cysts, the concentrations of IL-$1{alpha}$ were higher than IL-$1{eta}$, but not stastically significant (p>0.05). In odontogenic keratocysts, the concentrations of IL-$1{alpha}$ were significantly higher than IL-$1{eta}$ (p<0.05). In cystic fluid, the concentration of IL-$1{eta}$ was significantly higher than IL-$1{alpha}$ (p<0.05). 3. Between odontogenic keratocysts and radicular cysts, the concentrations of IL-$1{alpha}$ were significantly higher in odontogenic keratocysts than in radicular cysts (p<0.05). 4. For TNF-${alpha}$, only cystic fluid group showed significantly higher concentrations than the control group (p<0.05).