The purpose of this study is evaluating about the survival rate and causes of failed implants. In this study, the 371 implants was evaluated for the survival rate and failing factors of implant. The survival rate was 96.5%. The failure rate was 3.5%. The average life time of implants was 50 months. The average age of patients treated was 49 years old. In total 371 cases, 13 cases failed implants were removed. The causes of failing implants were poor oral hygiene, excessive occlusal loading, smoking, and etc. The leading causes of failed implants were improper oral hygiene and excessive occlusal loading. In conclusion, I suggest that the periodic plaque control and occlusal force management can improve the survival rate of implants.