Abstract: Objective To explore the relationship between the baseline dialysate to plasma creatinine ratio at 4h and restless legs syndrome(RLS) in maintenance peritoneal dialysis(PD) patients. Methods From December 1, 2019 to June 31, 2020, 92 hospitalized PD patients were recruited to assess peritoneal transport function and dialysis adequacy. Regular follow-ups were conducted. During hospitalization, RLS was screened according to the diagnostic criteria of International Restless Legs Syndrome Study Groupand the prevalence of RLS evaluated. They were divided into two groups of RLS(RLS+ group) and non-RLS(RLS-group) according to whether or not RLS occurred. All of them were evaluated for basic peritoneal transport function within 6 months after PD catheterization. To relationship was analyzed between baseline dialysate to plasma ratio of creatinine at 4h(4hD/Pcr) and RLS and the predictive value of baseline 4hD/Pcrfor RLS examined. Results The prevalence rate of RLS was 33. 7% and moderate-to-severe cases predominated(moderate 35. 48%, severe 38. 71%). Age, dialysis age, baseline 4hD/Pcr and ferritin of RLS+ group were significantly higher than those of RLS-group while urine output was significantly less than that of RLS-group(all P<0. 05). Multivariate Logistic regression analysis indicated that advanced age(OR=1. 054, 95%CI 1. 010-1. 100, P=0. 015), lower urine output(OR=0. 998, 95%CI 0. 997-0. 999, P=0. 005) and higher baseline 4hD/Pcr(OR=1. 047, 95%CI 1. 009-1. 086, P=0. 014) were independent risk factors for RLS. Receiver operating characteristic(ROC) curve showed that the sensitivity of baseline 4hD/Pcr for predicting the risk of RLS was 90. 3% and the specificity 45. 9% in PD patients. Conclusion Advanced age, lower urine output and higher baseline 4hD/Pcrare independent risk factors for RLS in PD patients. And high baseline 4hD/Pcr has some diagnostic and predictive value for RLS in PD patients.