Thyroid disorders are highly prevalent, occurring most frequently in aging women. Thyroid-associated symptoms are very similar to symptoms of the aging process; thus, improved methods for diagnosing overt and subclinical hypothyroidism in elderly people are crucial. Thyrotropin measurement is considered to be the main test for detecting hypothyroidism. Combined evaluations of thyroid stimulating hormone (TSH) and free-thyroxine can detect overt hypothyroidism (high TSH with low free-thyroxine levels) and subclinical hypothyroidism (high TSH with normal free-thyroxine levels). It is difficult to confirm the diagnosis of thyroid diseases based only on symptoms, but presence of symptoms could be an indicator of who should be evaluated for thyroid function. The most important reasons to treat overt hypothyroidism are to relieve symptoms and avoid progression to myxedema. Overt hypothyroidism is classically treated using L-thyroxine; elderly patients require a low initial dose that is increased every 4 to 6 weeks until normalization of TSH levels. After stabilization, TSH levels are monitored yearly. There is no doubt about the indication for treatment of overt hypothyroidism, but indications for treatment of subclinical disease are controversial. Although treatment of subclinical hypothyroidism may result in lipid profile improvement, there is no evidence that this improvement is associated with decreased cardiovascular or all-cause mortality in elderly patients. In patients with a high risk of progression from subclinical to overt disease, close monitoring of thyroid function could be the best option.