Objective · To investigate the effect of peritonitis on all-camortality and cardiovascular mortality of peritoneal dialysis (PD) patients. Methods · January 2003 to September 2017, 614 patients treated with PD in the Department of Nephrology of Ruijin Hospital, Shanghai Jiao Tong University School of Medicine were retrospectively included. The patients were divided into the peritonitis group and the peritonitis-free group according to whether peritonitis occurred after PD treatment. According to the first standard peritoneal equilibrium test results, the patients were divided into low transport group (L group), low average transport group (LA group), high average transport group (HA group) and high transport group (H group). The study endpoints were defined as all-camortality or cardiovascular mortality. The demographic data, clinical data at baseline (within one month of starting PD treatment) and PD outcomes were compared between the peritonitis group and the peritonitis-free group. The proportional hazards model (Cox model) was established to analyze the effect of peritonitis on all-cadeath or cardiovascular death. Results · In the peritonitis group (213 cases), 125 patients (58.7%) were positive for pathogenic bacteria, in whom 69 patients (32.4%) were Gram-positive bacteria, 46 patients (21.6%) were Gram-negative bacteria, and 6 patients (2.8%) were fungi. Compared with the peritonitis-free group, the patients in the peritonitis group had longer dialysis duration (P0.000), older age (P0.001), higher proportion of lower education level (P0.000), higher proportion of patients with cerebrovascular disease and diabetes mellitus (P0.004, P0.036), and lower serum albumin level (P0.016). Multivariate Cox regression analysis showed that peritonitis was an independent risk factor for all-camortality and cardiovascular mortality (P0.015, P0.046) after age, diabetes mellitus, serum albumin and other factors being adjusted. Subgroup analysis showed that compared with the patients with high educational level, the risk of all-camortality [HR: 1.99 (1.14-3.46) vs 1.39 (0.74-2.62)] and cardiovascular mortality [HR: 1.95 (0.89-4.25) vs 1.14 (0.50-2.61)] were more intensively increased in patients with low educational level after peritonitis. Compared with the H group+HA group, the risk of all-camortality [HR: 2.31 (1.30-4.11) vs 1.22 (0.70-2.12)] and cardiovascular mortality [HR: 3.24 (1.41-7.42) vs 0.95 (0.45-2.02)] were more intensively increased in the L group+LA group after peritonitis. Conclusion · Peritonitis is an independent risk factor for all-camortality and cardiovascular mortality of PD patients. The risk of all-camortality and cardiovascular mortality after peritonitis increases more significantly in those with lower educational level or in L group+LA group than those with higher educational level or in H group+HA group.