Background: The aim of this study is to evaluate the use of carbamazepine as primary definitive diagnostic aid in patients with classical/idiopathic and symptomatic/pathological trigeminal neuralgia by analyzing the pain relief. Advantages of using carbamazepine is its easy availability, cost effective, non-invasive, no machine needed, simple, no specialized team needed and is itself a mode of treatment for trigeminal neuralgia as compared to MRI and CT. Methods: 100 patients with clinical characteristics signifying trigeminal neuralgia were included in this study in the age group of 50-65 years from both sexes who were examined clinically and radiographically. Sensory input of trigeminal nerve, gross motor input, diagnostic analgesic blocking and 0.5cc of normal saline at test site is also used to differentiate pain. All 100 patients were given tab. carbamazepine 100 mg twice daily to analyze the pain relief. Results and Conclusion: Clinical signs and symptoms were present in all 100 patients who were given tab. carbamazepine. 76 patients without any known cause for trigeminal neuralgia responded well so had pain relief and other 24 patients did not responded and had pain existing who on further evaluation were diagnosed with symptomatic trigeminal neuralgia due to some other irrelevant pathological causes. This suggests response to treatment with tab. carbamazepine as pain relief can be used as a universal primary definitive diagnostic aid in patients with trigeminal neuralgia. Failure to obtain any improvement with this treatment should bring the diagnosis into question? Sometimes patient is not able to afford costly investigations like MRI and CT, hence the medical management can be started with tab. carbamazepine to diagnose the condition. We recommend MRI and CT as further secondary investigations to rule out cause for symptomatic trigeminal neuralgia due to some other irrelevant pathological causes. Keywords: Carbamazepine, Definitive Diagnostic Aid, MRI and CT, Trigeminal Neuralgia.