Grade 2,3 and 4 hypothyroidism in the elderly, globally defined as subclinical hypothyroidism, is the object of this minireview. Attention is focused on the prevalence, on the causes and particularly on the clinical features that, in spite of the definition, frequently occur: these are summarized in cognitive impairment, mood disorders, lipid dysmetabolism, cardiovascular abnormalities. Finally a diagnostic algorithm is proposed for the selection of patients to be treated. The authors are of the opinion that a general screening with serum TSH assay for elderly hospitalized patients is worthwhile.