Over a 3-year period 22 episodes of peritonitis were observed among 20 patients treated for end-stage renal failure by CAPD. This represents an overall incidence of 1 episode every 9.5 patient-months (1/14.2 months in 1981, 1/11.3 months in 1982). Eight patients out of 20 never developed peritonitis, and 6 had one episode only. Cocci + were the most frequent culture finding. Two episodes of mycotic peritonitis and 1 sterile peritonitis were observed. Antibiotic treatment was generally successful within 24 h. The incidence of peritonitis was higher among diabetic (1/7 months) than among non-diabetic patients (1/12.6 months). Patient selection, the bag connection technique and the experience accumulated by the dialysis team appear to be the principal factors in lowering the incidence of this complication.