Abstract : Lateral medullary syndrome defined as ischemia of the lateral part of the medulla oblongata occurs due to thrombosis of posterior inferior cerebellar or the vertebral artery and patient usually presents with crossed hemisensory loss, cerebellar signs and ipsilateral Horner syndrome. In our case, on examination no limb weakness was noticed. Right side Horner syndrome characterized by right eye enophthalmos, partial ptosis (grade 1) with miosis, pupil reacting to light and no anhidrosis or hemisensory loss over face. Paralysis of Right glossopharyngeal and vagus nerve was present. Right side nystagmus and cerebellar ataxia was present, and deep tendon reflexes were depressed on right side. MRI Brain with angiography showed infarct at right sided posterolateral portion of medulla and cerebellar hemisphere due to right vertebral artery thrombosis with patchy flow. Treated with Antiplatelet, statin, Ryles tube feeding and stockings applied to prevent deep veins thrombosis.