Studied was the bilirubin equilibrium in 62 normal cows, 52 cows with clinical ketosis, 31 cows with diffuse liver injury, and 14 cows that went off food for five days. A moderate rise of the total bilirubin of mixed type was found in ketosis-affected cows. Statistically significant proved the changes in the free fraction, however, there were no persuasive data that they were due to superproduction of bilirubin. Changes in the total bilirubin similar to those in cows with ketosis were established also in cows subjected to starvation, substantiated by the adequate rise of the free and the bound fraction. The hyperbilirubinemia in cows with diffuse liver injuries was found to be of a mixed type, with a very clear transposition in the bilirubin fractions. The direct: indirect ratio of bilirubin in this case was higher than unit, and the percent participation of the indirect fraction was brought down to 42.5. Apparently, the symptoms of liver affections were beyond the frames of what was found in the cows with ketosis. With the use of tests for the demonstration of urobilin and urobilinogen in the urine no dependable idea could be found of the status of the pigment fraction in the liver of ketosis-affected cows or the fact that this fraction was involved to a considerable extent. Discussed is the possibility of linking the state of hyperbilirubinemia in cows with ketosis with some energy deficiency with regard to the plasma glucosis and the liver glycogen.