Résumé : To evaluate the influence of age on clinical findings of thyroid disease, the records of 209 consecutive hospitalized patients with hyperthyroidism (n = 109) or hypothyroidism (n = 100) over a ten year period (1979 to 1988) were retrospectively reviewed. Patients included 51 males and 158 females, aged 21-99 years. Control euthyroid subjects (n = 70) were selected in the same age range and for similar non-thyroid illness as patients. Patients and controls were sorted by age decade of life. For each group a clinical index was calculated on the basis of 10 symptoms and 10 signs most frequently observed in thyroid disease. With increasing age, the occurrence rate of the clinical manifestations of thyroid disease decreased in patients while it increased in controls. This opposite evolution was less marked in hypothyroidism than in hyperthyroidism and was independent of biological parameters which remained stable whatever the age of patients and controls. Specific clinical features were identified for hyper- and hypothyroidism but none of them had sensitivity higher than 60% except goiter in hyperthyroid patients aged 61-80. In conclusion, a clinical diagnosis of thyroid disease is difficult in aged subjects because there are only a few specific features and their frequency is low. Therefore, in subjects over 60 years, we advocate performance of thyroid biochemical screening.