Objective To provide guide for prevention and cure of peritonitis in peritoneal dialysis(PD) by comparing the causative organisms and clinical outcome of PD related peritonitis in younger and elderly patients in our center.Methods All patients who developed PD related peritonitis between January 2006 and December 2013 in Wuhan NO.1 hospital were included.According to their age,episodes were divided into younger patients group (＜ 65 years) and elderly patients group (≥65 years).The microbiology and clinical outcome of PD related peritonitis were compared,and the related risk factors of the treatment failure were analyzed.Results Three hundred and sixty-six episodes of peritonitis occurred in 258 patients during the study period.The overall rate of peritonitis was 1 episode in 76.8 patient-months.Elderly patients had higher incidence of peritonitis (1 episode every 56.4 months vs 1 episode every 88.7 months,P=0.001),higher incidence of fungus infection (9.6％ vs 3.9％,P=0.026) and higher mortality (46.2％ vs 14.0％,P=0.001) than that in younger patients.Cox regression analysis showed that longer duration of PD treatment and fungal peritonitis were both risk factors of the treatment failure.Conclusion Elderly patients had higher incidence of peritonitis,higher incidence of fungus infection and higher PD-related mortality than younger patients.