The purpose of this study is to find the histopathological pattern of cysts. We reviewed the hospital chart, out-patient chart, roentgenogram, histopathologic report and operation report of 152 patients who had been diagnosed as cyst and treated at the department of Oral and Maxillofacial Surgery of Korea university hospital between Jan. 1, 1995 and Dec. 31, 1998. And then we studied clinically with regard to pathological classification, age and sex distribution, anatomical distribution and so on. The results were as follows : 1. In pathologic classification, radicular cyst (97cases, 64%), dentigerous cyst (35cases, 23%), odontogenic keratocyst (8cases, 5.3%) were dominant among cases of cyst. 2. The pattern of age distribution in cases of radicular cyst, dentigerous cyst and odontogenic keratocyst was similar to that found in previous studies. The peak incidence was in the second decade (27%) and third decade (29%) in overall cases. 3. The male-to-female ratio was 1.9 : 1. 4. Radicular cyst occured most frequently in the maxillary incisor teeth area, dentigerous cyst in mandibular wisdom teeth area, and odontogenic keratocyst in mandibular molar area.