Haemophilus influenzae is a rarely reported cause of peritonitis in chronic ambulatory peritoneal dialysis (CAPD) patients. In this report, a peritonitis case due to H. influenzae in a 32-years-old female patient with end-stage renal failure receiving CAPD for 7 years, has been reported. The patient was admitted to our clinic with the complaints of nausea, vomiting, abdominal pain, and cloudy dialysate. She had diffuse abdominal tenderness, however, other systems and peritoneal catheter exit site were found to be normal in physical examination. White blood cell (WBC) count in peritoneal fluid was 1.500/mm(3) with 90% neutrophils. Gram stain of the peritoneal fluid yielded moderate number of polymorphonuclear leucocytes but no microorganism. Empirical antibiotic therapy with vancomycin and amikacin was initiated intraperitoneally. Peritoneal fluid and blood cultures were performed using BacT/ALERT (R) (bioMerieux, NC, USA) blood culture system. Although no growth was detected in the blood sample at the end of the 5 days, growth was observed in the peritoneal sample within 48 hours. Gram staining of the positive bottle revealed gram-negative coccobacilli. At the end of an overnight incubation period, the colonies, which grew on chocolate agar, were identified as H.influenzae by using API NH system (bioMerieux, NC, USA). The isolate was found to be beta-lactamase-negative. The antibiotic regimen was switched to cephazoline 2 g/day intraperitoneally. The patient rapidly recovered and the WBC count of the peritoneal effluent decreased to 70/mm(3). The therapy was continued for 21 days and she was discharged. The peritoneal catheter was not removed. During 7 months after the therapy, peritonitis did not recur. In conclusion, H.influenzae should be kept in mind as a cause of peritonitis in CAPD patients even though it is an unusual agent and the infection may be successfully treated with intraperitoneal antibiotics without removal of peritoneal dialysis catheter.