Abstract
The excretion of free cortisol in the urine of patients with Cushing''s syndrome is in excess of normal, and frequently the amount is many times the upper limit of normal. In patients with Cushing''s syndrome due to adrenocortical hyperplasia the response to the administration of corticotropin was far greater than that shown by normal subjects. One patient with an adrenocortical adenoma showed no response to corticotropin. Measurement of cortisol excretion may be of diagnostic importance in cases of Cushing''s syndrome when the group tests for corticosteroids yield equivocal findings.