Our experience of peritonitis in 156 patients over an 8-year period represents 186 episodes of peritonitis and 4,964 patient-months of CAPD. The incidence of peritonitis was significantly greater (1 episode every 8.6 patient-months) when the Oreopoulos technique was used and dropped to 1 episode every 43.3 patient-months when the Y set system was used. Of the 109 patients using the Y set system, 88 (80.7%) never had episodes of peritonitis, whereas only 7 (16.7%) of the 42 patients using the Oreopoulos technique were free of peritonitis. For 23 patients shifted from the Oreopoulos to the Y set technique, the incidence of peritonitis dropped from 1/9.8 to 1/35.2 episodes/patient-months.