BACKGROUND: Increased blood urea nitrogen (BUN) levels have been demonstrated to be associated with broader metabolic disturbances and the incidence of type 2 diabetes (T2D), potentially playing a role in the development of diabetic complications, including diabetic peripheral neuropathy. AIM: To examine the relationship between BUN levels and peripheral nerve function in patients with T2D. METHODS: This observational study involved the systematic recruitment of 585 patients with T2D for whom BUN levels and estimated glomerular filtration rate were measured. Electromyography was used to assess peripheral motor and sensory nerve function in all patients, and overall composite -scores were subsequently calculated for nerve latency, amplitude, and conduction velocity (NCV) across the median, ulnar, common peroneal, posterior tibial, superficial peroneal, and sural nerves. RESULTS: Across the quartiles of BUN levels, the overall composite -score for latency ( = 38.996, for trend < 0.001) showed a significant increasing trend, whereas the overall composite -scores for amplitude ( = 50.972, for trend < 0.001) and NCV ( = 30.636, for trend < 0.001) exhibited a significant decreasing trend. Moreover, the BUN levels were closely correlated with the latency, amplitude, and NCV of each peripheral nerve. Furthermore, multivariate linear regression analysis revealed that elevated BUN levels were linked to a higher overall composite -score for latency (β = 0.166, = 3.864, < 0.001) and lower overall composite Z-scores for amplitude (β = -0.184, = -4.577, < 0.001) and NCV (β = -0.117, = -2.787, = 0.006) independent of the estimated glomerular filtration rate and other clinical covariates. Additionally, when the analysis was restricted to sensory or motor nerves, elevated BUN levels remained associated with sensory or motor peripheral nerve dysfunction. CONCLUSION: Increased BUN levels were independently associated with compromised peripheral nerve function in patients with T2D.