Objective To investigate the diagnostic efficacy of serum pentosidine as a biomarker in patients with diabetic erectile dysfunction.Methods Forty patients with type 2 diabetes were included and divided into diabetic erectile dysfunction and diabetic non-erectile dysfunction groups based on the RigiScan ? test results. The differences between their clinical data and serum pentosidine levels were compared, and the correlation between serum pentosidine and clinical indicators was analyzed. The diagnostic efficacy of serum pentosidine in the diagnosis of diabetic erectile dysfunction was assessed by a one-way ROC curve.Results Serum pentosidine levels were significantly higher in the diabetic erectile dysfunction group compared to the diabetic non-erectile dysfunction group (P < 0.05); serum pentosidine level was positively correlated with UA/CR (r =0.343, P <0.05), were negatively correlated with the number of erectile events (r = -0.397, P < 0.05) and erection duration (r = -0.403, P < 0.05); the prevalence of diabetic erectile dysfunction increased with the rise in serum pentosidine; the receiver operating characteristic curve had the AUC of 0.785 and the sensitivity of 90.91%.Conclusion Serum pentosidine is expected to be a new marker for diabetic erectile dysfunction.