Cervical incompetence is an important cause of midtrimester abortion. However, the etiology and diagnostic method have still not been established. This retrospective study was aimed to review epidemiology, management and outcome of cervical incompetence in Ramathibodi Hospital, Mahidol University, Thailand, from 1982 to 1997. Fifty seven patients were diagnosed as having cervical incompetence during this period. Fifty patients had elective cerclage. Seven patients had emergency cerclage. Success rate in this study was 94.6 per cent. Only 7 per cent of patients had complications such as chorioamnionitis and suture displacement. There was no other serious complication after treatment. Nowadays, there is still no established method to diagnose cervical incompetence in pregnancy. Treatment is usually based on past obstetric history. Cervical cerclage is an established treatment for this problem. Emergency cerclage is still controversial. The prevention is to avoid any procedure which can cause cervical trauma leading to cervical incompetence.