Peritonitis remains the leading cause of the patient dropout in CAPD in many developing countries. In Korea, 71% of CAPD patients dropout is caused by peritonitis. To elucidate an adequate guideline for treating peritonitis in our country, we analyzed clinical and bacteriologic profiles of peritonitis(1995. 1. 1- 1999. 12. 31). Two hundred and twenty eight episodes of peritonitis were developed in 127/247 patients. The incidence of peritonitis was 0.41/patient-year in general, which was decreased to 0.24/patient-year in 1999. The incidence of causative organisms were as follows; 82(36.0%) by Gram positive organisms, 38 (16.2%) by gram negative organisms, 16 cases(7.0%) by mixed organsisms, and 5 cases(2.2%) by fungus. During study period, the incidence of peritonitis by gram positive organsism was decreased while the incidence of peritonitis by gram negative organism was not changed. Recurrent infection/relapse was noted in 58 patients(45%). Peritonitis were eradicated only in 66% of the cases by initial antibiotics(cefazolin+aminoglycoside); and another 17% responded by second line antibiotics. Peritoneal catheters were removed in 38 episodes(16.7%). Patients with exit infection were more frequent in removal of catheter. Risk factor analysis was performed in 146 patients, who were newly started CAPD. There were 60 initial episodes of peritonitis(mean duration of follow up was 16.7 patient months). Sixty-five percent were free of peritonitis at the end of first year, 54% at the end of second year and 45% at the end of third year (Kaplan-Meier). Factors such as age, sex, underlying DM, were not risk factor for CAPD peritonitis. In conclusion, we observed that the incidence of peritonitis decreased every year. It was revealed however that only 66% of peritonitis can be successfully treated by first line antibiotics. Second line antibiotics such as ceftazidime may need to be introduced in early phase of CAPD peritonitis. Up to one third of patients had recurrent infection/relapse, which raised the incidence of peritonitis. Continuing education as well as better exit care is needed to improve technical survival of CAPD patients in Korea.