Thyroid function has been studied in 24 patients judged to have saturnism on the basis of their urinary excretion of lead following an infusion of edetate calcium disodium. Following administration of sodium iodide I 131 the mean 24 hour131I uptake for 23 was 10.0% ± 3.7% SD. A single patient had an uptake of 26.1%. All but three patients responded normally to stimulation with thyroid stimulating hormone. Of two patients studied, one had a decreased secretion of thyroxine by the thyroid. Other measures of thyroid function were normal in the group. The findings are consistent with injury of the iodine concentrating mechanism of the thyroid.