The outcomes of all continuous ambulatory peritoneal dialysis-related infections due to Pseudomonas aeruginosa (n = 33) were analyzed and compared with the outcomes of infections due to all other microorganisms (n = 663) over a seven-year period. There were 16 catheter infections (exit site or tunnel infection or both), seven episodes of peritonitis, and 10 episodes of catheter infections associated with peritonitis due to P. aeruginosa. Catheters were removed in 58 percent (19 of 33) of the infections due to P. aeruginosa, but in only 16 percent (104 of 663) of the infections due to other organisms (p less than 0.01). All P. aeruginosa catheter infections associated with P. aeruginosa peritonitis resulted in catheter loss. P. aeruginosa catheter infections not associated with peritonitis also often did not resolve with antibiotic therapy (nine of 16 or 56 percent of catheters removed compared with 42 of 317 or 13 percent of catheters removed for other organisms, p less than 0.01). However, P. aeruginosa peritonitis episodes that were not associated with a catheter infection were no more likely to result in catheter loss than were peritonitis episodes due to other organisms (one of seven compared with 37 of 256, 14 percent for both). It is concluded that catheter infections due to P. aeruginosa with or without associated peritonitis usually require catheter removal. Conversely, P. aeruginosa peritonitis without a catheter infection often does not require catheter removal.