In 16 patients under CAPD, 29 cases of bacterial peritonitis were observed, with clinical manifestations in 23. The mean cell count in peritoneal dialysis fluid was 5608/mm3 with 4991/mm3 polymorphonuclear, Leukocytes Causative pathogens were Staphylococcus in 14 cases, Streptococcus in 6, Bacillus in one, Enterobacteria in 5, Pseudomonas aeruginosa in 1 and Moraxella in 1. Three cultures were negative. First choice treatment was a daily intraperitoneal injection of 1 g of ceftriaxone. 79.3% of patients recovered within 5 days. Failure were due to a Methicillin-resistant Staphylococcus epidermidis in one case, a Streptococcus faecalis in two cases, and a Staphylococcus aureus in three observations, which two were responsible of abscess round catheter peritoneal. Mean ceftriaxone concentrations 24 hours after the intraperitoneal injection were 50.6 mg/l (range: 3.3-141 mg/l) in serum and 58.1 mg/l (range: 4.3-180 mg/l) in dialysate. These concentrations are greater than most of ceftriaxone's MICs for susceptible bacteria, a finding that confirm the value of treatment with a single daily intraperitoneal injection of ceftriaxone.