In patients with pancreatitis an increase of the total amount of alkaline phosphatase (ALP; EC 3.1.3.1.) and the appearance of its macro isoenzyme which paralles the decrease of bone isoenzyme was found. This isoenzymatic profile suggests that the increase of ALP in pancreatitis is due to the concomittant hepatobiliary disorder. Moderate increases of ALP didn't appear to be related to the existence of gallstones.