1. The activity of dopamine-beta-hydroxylase (DBH) was assayed in the serum of 102 patients, mostly with varying degrees of hepatic dysfunction. 2. DBH activity was not elevated in those with liver disorder and did not correlate with serum bilirubin, transaminase, lactic dehydrogenase, alkaline phosphatase or creatine phosphokinase. 3. It is concluded that the liver is not necessarily involved in the inactivation of DBH.