To determine the incidence and outcome of spontaneous viscus perforation in peritoneal dialysis (PD) patients and which factors could facilitate early diagnosis.A retrospective chart review was done on all patients with viscus perforation and on a control group with peritonitis secondary to gram-negative organisms.A tertiary care University Hospital Peritoneal Dialysis program.All patients with surgically proven spontaneous viscus perforation from 1978 to June 1992 (n = 15). A group of control patients (n = 15) with gram-negative bacterial peritonitis was also reviewed for comparison.None.Hospital days, patient survival after perforation, and return to peritoneal dialysis were the main outcomes measured. Peripheral white blood cell (WBC) count, PD fluid WBC count with differential, PD fluid cultures, radiologic information, and surgical intervention were also evaluated. Data were analyzed using the Mann-Whitney test to determine significant differences between the two groups.Viscus perforation occurred in 15 of the 431 patients on PD from 1978 to June 1992 (3.5%). In comparison to the control group, patients with viscus perforation had a significantly higher peripheral WBC count (p = .016), a higher mean PD fluid WBC count (p = .006), and a higher mean percentage of polymorphonuclear cells in the PD effluent (p = .038). Multiple organisms on PD fluid cultures were noted in 12 of 15 patients with perforation and in only 3 control patients. Pneumoperitoneum was seen on abdominal or chest radiograph or computerized tomographic (CT) scan in 10 of 15 patients with perforation and in only 1 of 15 patients in the control group. All patients with viscus perforation required surgery and 6 expired. Only 1 death occurred in the control group. Only 1 of the 9 patients surviving perforation was able to resume PD, in contrast to 13 of 14 surviving control patients.We conclude that viscus perforation is associated with high morbidity, mortality, and technique failure. Diagnosis may be made by repeatedly searching for intraperitoneal free air on radiograph or CT scan in patients with persistently elevated peripheral and PD fluid WBC count, and for multiple organisms on PD fluid culture.