BACKGROUND Malnutrition-Inflammation Score (MIS) has proved to predict the prospective mortality in maintenance hemodialysis (MHD) patients. However, its value of long-term mortality predictability in peritoneal dialysis (PD) patients has not been adequately studied. METHODS A total of 155 chronic stable PD patients from November 2005 to December 2006 were enrolled. At baseline, the MIS, Subjective Global Assessment (SGA), as well as clinical, laboratory, and anthropometric parameters were recorded. All patients were followed until October 2009 to evaluate mortality as a primary outcome. RESULTS The MIS correlated very well with SGA and other nutrition and inflammation markers. Patients with a higher MIS had a worse survival rate compared to those with lower MIS. After adjusting for potential confounding factors, one unit increase of MIS was associated with a 1.27-fold greater death risk (hazard ratio: 1.27, 95% confidence interval: 1.19 - 1.36; p < 0.001). MIS had a superior mortality predictability compared with SGA. Moreover, univariate and multivariate analyses denoted MIS, age, dialysis vintage, and comorbidities as independent predictors of total mortality. CONCLUSION MIS is a promising marker for malnutrition inflammation assessment and an independent predictor of long-term mortality in Chinese PD patients.