CT number of the liver is very important in the diagnosis of diffuse liver disease and difference between liver and spleen CT number in normal adults is invaluable in predicting the presence of liver disease. Authors measured Ct numbers of the liver and the spleen in 100 normal adults. The results were as follows: 1. In pre-enhancement scan liver CT number is higher them that of the spleen by 5-7 units (P<0.001). 2. In post-enhancement scan each liver and spleen CT number of male is lower that of female that that of female by 46 units (P<0.01 in liver, P<in spleen). 3. Contrast infusion increases the CT numbers of the liver proportionaly to the CT numbers of the spleen of the same patients. 4. CT numbers of liver and spleen have no definite correlation with age.