Thyreotoxicosis in the elderly: aspecific signs may cause a delay in diagnosis.The clinical manifestations of thyroid diseases in the elderly are often atypical and can easily be attributed to other medical conditions or 'normal aging'.Two nursing home patiënts with hyperthyroidism are described. Due to the atypical presentation of the thyroid disease their complaints were attributed to other conditions. In both patients there was a significant delay in diagnosis and treatment of hyperthyroidism.In elder patiens signs and symptoms of thyreotoxicosis are frequently related to cardiovascular, gastrointestinal and neuropsychiatric disorders. Most often occur atrial fibrillation, worsening of cardiac failure and angina pectoris, weight loss, anorexia, constipation, cognitive impairment and delirium.Delay of diagnosis and treatment of hyperthyroidism may be potentially harmful to the patient. Untreated thyreotoxicosis may lead to serious cardiovasculair complications (particularly cardiac failure and cerebrovascular accidents), mental deterioration and osteoporosis.In elder people with unexplained and vague signs and symptoms thyroid function should always be checked. The TSH assay is a very accurate diagnostic test for screening thyroid function. A normal TSH indicates euthyroidism with an accuracy of almost 100%.The medical treatment for hyperthyreoidism in the elderly are antithyroid drugs. When an euthyroid state is rendered, suppletion with L-thyroxine may be nessecary. Radioactive iodine treatment is preferred in some cases though there may be practical difficulties with the application of this treatment in nursing home patients because temporary isolation is necessary.