Diabetic cranial neuropathy is one of complications of diabetes mellitus , blink reflex used to diagnose subclinical cranial neuropathy. Forty patients with type 2 diabetes mellitus (20 with PN,20 without PN), their ages ranged from 30-60 years examined clinically, neurologically, and electrophysiologically. Blink reflex and nerve conduction studies (motor, sensory) for upper and lower limbs were performed for all patients. The blink reflex and nerve conduction studies were compared to 20 normal subjects and their age ranged also from 30-60 years. R2C latency is the most sensitive parameter in blink reflex response which can help in diagnosis of subclinical diabetic neuropathy, Alteration of blink reflex correlate with disease severity and duration.