Transcatheter arterial embolization (TAE) was performed in 2 patients with Cushing's syndrome caused by adrenal adenoma by using a mixture of absolute ethanol and iohexol. In 1 patient successful suppression of the hypersecretion of cortisol has continued for 9 months after TAE without complications. However, in the other patient, TAE was discontinued due to marked hypertension and tachycardia induced by a massive release of catecholamines from the embolized "normal" part of the tumor-bearing adrenal gland during the procedure. These results suggest that it is important to perform TAE of only the arterial branches feeding the tumor.