To identify the resonable criteria in dedtection of the degree of Fatty liver, we prospectively evaluated sonograms and CT scans in 33 Patients With bright liver on sonography. On sonograms, we analyzed the echogenicity of the liver, acoustic attenuation, and visualization of the portal vein and the diaphragm, Each criterion was scored from 0 to 2. CT criterion for fatty liver was assessed by the attenuation difference between the liver adn the spleen on nonocontrast CT scans, The average sonographic grade for CT Grade I was 1.3, Grade II was 2.1,and Grade III was 2.8. The accurate dedtction rate of each sonograhic grade was as follows, Grade