We analysed 27 patients (15 women and 12 men) on CAPD treatment longer than 6 months at the Clinic of Nephrology, CCS, in Belgrade. Pts were between 22 and 72 years old (57.77 +/- 12.21 years). These pts had 47 episodes of peritonitis: 6 pts (22.22%) were without peritonitis, but 21 pts (78.22%) had between 1 and 5 episodes of peritonitis. We found 1 peritonitis /pts/year. Causes of peritonitis were mostly unknown (27/47) because treatment had began before taking culture of the peritoneal dyalisate. The most common causes of peritonitis were coagulase negative staphylococci: Staphylococcus aureus (8) and Staphylococci epidermidis (8). Laboratory showed: leucocytosis, hyperfibrinogenaemia, hypoproteinaemia and accelerated ESR. There was no connection between causes of chronic renal failure and frequency or peritonitis. During treatment of peritonitis in 2 pts we had to replace the peritoneal catheter and 5 pts went on haemodialyses. The other were recovered and continued CAPD treatment.