The author analyzed 243 cases clinically and radiographically which were diagnosed as odontogenic cyst in SNUH during 10 years (1974. 1 - 1983. 12). The obtained results were as follows: 1. This cyst occurred more frequently in male than in female and the incidence was the highest in the 3rd decade. 2. Maxilla was more frequently affected than mandible 3. Most of the odontogenic cysts were unilocular type (236 cases, 97.1%), showing distinct border (242 cases, 99.6%) with smooth margin (222 cases, 91.7%). 4. The adjacent teeth showed root resorption in 57 cases (23.5%), and root divergence in 52 cases (21.4%). 5. The cyst in lower jaw caused the displacement of the mandibular canal wall in 30 cases (31.25) 4. and root divergence in 52 5. 6. The cyst in upper jaw extended to the maxillary sinus in 61 cases (41.5%)