Objective: Review physiologic thyroid function changes with aging and emphasize careful interpretation of tests in the aging population. Methods: Literature review.Results: Using age-specific thyroid-stimulating hormone (TSH) reference ranges should minimize or avoid the unnecessary diagnosis of thyroid disease in elderly patients. Subclinical thyroid dysfunction and abnormal TSH with normal thyroid levels may improve with time, so careful monitoring of thyroid function is recommended. Overt thyroid disease should always be treated. Conclusion: Clinical judgement is always warranted to decide how and when to treat subclinical thyroid disease in the elderly.