Abstract: Objective：To investigate the value of C peptide release level in screrning and diagnosis of type 2 diabetes mellitus with asymptomatic diabetic peripheral neuropathy (DPN). Methods：A total of 600 cases of type 2 diabetic inpatients without neurological symptoms were enrolled from the Department of Endocrinology, Zhongshan Hospital from January to December, 2016. Each patient received complete history taking, physical examination, serum biochemical examination, arginine stimulation test, and electromyogram (EMG) examination. Results：Among the 600 cases of diabetic inpatients, 307 patients (51.2%) was diagnosed as asymptomatic DPN by EMG, among whom 173 cases (28.8%) had distal symmetric polyneuropathy (DSPN) and 134 cases (22.3%) had focal asymmetric DPN. Patients with asymptomatic DPN were older and had longer disease course and poorer glucose control. Arginine stimulated release of C peptide was significantly decreased in patients with asymptomatic DPN (P＜0.05). Further analyses showed that reduction of C peptide level was an independent risk factor for asymmetric DSPN (P＜0.01) but not for focal DPN. The area under the ROC curve for the combination of fasting C peptide with age, gender, course of diabetes, and HbA1c in diagnosing asymmetric DSPN was 0.758 (95%CI 0.720 to 0.792, P=0.032). Conclusions：Reduced arginine stimulated C peptide level is an independent risk factor for asymptomatic DSPN, and may indicate latent DSPN in type 2 diabetes patients.