Background:Acute ischemic stroke and thyroid conditions have complicated interactions. With mixed findings, earlier research has suggested a link between thyroid function and the severity and outcome of strokes.Aim: Toevaluate the impact of thyroid function on acute ischemic stroke patient's functional outcome and stroke severity.Patients and methods:This prospective cohort study, which comprised 70 patients admitted within 48 hours of the beginning of their first acute ischemic stroke, was carried out at the Stroke and Critical Care Units of the Neurology Department at Zagazig University Hospitals. On admission, routine laboratory tests and thyroid hormone levels were examined. Modified Rankin scales (mRS) and the National Institute of Health and Stroke scale (NIHSS) were used to measure the severity of the stroke and the functional outcome, respectively.Results:In 41% of patients, abnormal thyroid function was found. Non-thyroid sickness syndrome was the thyroid anomaly that was most frequently noted (low FT3). Stroke severity and a poor outcome were substantially correlated with high TSH and low FT3. Conclusion: The severity and functional prognosis of an ischemic stroke may be predicted by abnormal thyroid hormone levels at presentation