BackgroundChronic kidney disease (CKD) is very common now and is associated with high overall and cardiovascular mortality. Numerous studies have reported that elevated heart rate (HR) is a risk factor for cardiovascular mortality. We investigated the link between serum endocan and circadian heart rate variability in non-dialysis stage 5 CKD patients.MethodsIn a cross-sectional study, we enrolled 54 prevalent n non-dialysis stage 5 CKD patients (32 males, aged 48.214.92years). HR was measured with an automatic system. Serum endocan level was analyzed by ELISA.ResultsNight/day HR ratio was independently predicted by serum endocan level (P<0.01) and hypertension history (P<0.05). Adjusted R-2 of the model was 0.222.Conclusion Increased serum endocan is significantly associated with circadian heart rate variability in non-dialysis stage 5 CKD patients. Further investigation is needed to explore the potential benefits of serum endocan lowering therapy in this patient group.