One of the uncommon gram negative organisms causing peritonitis in peritoneal dialysis patients is Citrobacter. Because of this organism's resistant nature, treatment for Citrobacter peritonitis may be difficult, and removal of the catheter may be necessary in refractory cases. Here we present 2 cases of peritonitis caused by this organism and fully treated with antibiotics. The literature contains only a limited number of reports on Citrobacter peritonitis, mostly case reports or portions of general papers about the microbiological spectrum of peritonitis in the relevant units. Until enough data about this micro-organism have been accumulated to map out an approach, it is wise to individualize treatment by watching the response of the patient during the wait for the antibiogram result and not to hesitate to remove the catheter if the clinical situation deteriorates.