Background: Hypothyroidism is associated with central and peripheral nervous system disturbances. It affects the CNS due to the impairment of the sensory pathways secondary to hormonal imbalances causing segmental demyelination. It also affects the transmission of impulses along the complex polysynaptic pathways, such as those mediating the blink reflex. Objective: Evaluation of Blink Reflex for early diagnosis of neurological dysfunction in hypothyroid patients and to study the response to treatment. Method: Blink Reflex was recorded using RMS EMG EP MK2 machine in 30 overt hypothyroid patients (serum TSH ?10 mIU/L) between 18 __ampersandsignndash; 50 years of age who were followed up after 3 months of treatment. Result: The latency of blink reflex showed an early ipsilateral R1 response and late R2 responses (ipsilateral R2i, contralateral R2c) which were found to be prolonged in the patients. Following the hormonal replacement therapy the latency tend to decrease while the amplitude was increased. Conclusion: Increased latency of blink reflex indicates impairment predominantly of the sensory pathways. These changes are further more altered in untreated patients in the advanced stage of the disease. Hence blink reflex is useful non-invasive tool for early detection of cranial neuropathy in newly diagnosed hypothyroid patients and to access their response to treatment.