Background: Sudden unexpected death (SUD) accounts for a significant proportion of overall mortality in patients undergoing peritoneal dialysis (PD).This study aimed to investigate the SUD clinical profiles in patients undergoing PD.Methods: Medical records from January 2009 to December 2018 were retrospectively reviewed in a hospital-facilitated PD center in Taiwan. Demographic data, laboratory parameters, comorbidities, drug history, physical performance status, cardiac function parameters, and peritoneal transport category were abstracted. Cox proportional hazard regression was used to determine hazard ratio(HR) in SUD clinical profiles in patients undergoing PD. Results: Based on 28 patients undergoing PD with SUD, 60 controls were matched for date of death on a 2:1 ratio for comparison. The incidence of diabetes and the prevalence of low physical performance status, analgesic drug use, concordant comorbidity number, mental health and chronic pain were higher in patients undergoing PD with SUD than in controls. In the cardiac function analysis, the QTc interval on the electrocardiogram was longer (467 vs. 453 ms, P=0.010) in patients undergoing PD with SUD than in controls. At 3 months before death, patients who experienced SUD demonstrated progressive lower serum potassium concentrations. Cox proportional hazard regression analysis revealed that diabetes [adjusted HR, 4.73; 95% confidence interval (CI), 2.75–8.14; P<0.001)] and mental health and chronic pain (adjusted HR, 2.07; 95% CI, 1.06–4.05; P=0.033) remain significant predictors for SUD in patients undergoing PD.Conclusions: Diabetes mellitus, mental health and chronic pain, incidence of hypokalemia before death are significant clinical factors for SUD in patients undergoing PD.