Four cases of adrenal tumors with unusually low attenuation coefficients are reported. The tumors presented with values ranging from 8 to 17 EMI units (EU: 500 scale) instead of the expected 30 to 40 EU range of the remainder of our adrenal tumors. Two of these patients had primary aldosteronism and two had Cushing's syndrome. An unusually high lipid content may be responsible for the lucent appearance.