We experienced 152 endosseous implant surgery and prosthodontic restoration with edentulous jaw for 5 years from Mar. 1990. to Oct. 1995. 422 fixtures were implanted. the ratio of male to female was 1.38 : 1 and the range of age from 16 to 74 years. Most dominant group was 41 to 50 years group(36%). In our study, implant success rates showed 96% in mandible and 92% in maxilla. The major causes of implant failure of primary osseointegration(75%), overloading(15%), neurologic problem(5%), psychologic problem(5%).