In order to identify risk factors in patients with acute cholangitis, 140 clinical, biochemical, etiologic, and pathologic variables of 449 attacks of acute cholangitis seen in one center over a 20-year period were analyzed. Simple regression revealed 24 factors with prognostic significance, but multivariate analysis detected only seven factors with independent significance in predicting mortality (acute renal failure, cholangitis associated with liver abscesses or liver cirrhosis, cholangitis secondary to high malignant biliary strictures or after percutaneous transhepatic cholangiography, female gender, and age). When the presence of each of these factors is weighted proportional to its coefficient of regression, patients with cholangitis could be scored on a scale of 0-27. A score of seven was clinically the most useful cut off--388 attacks of cholangitis associated with a score of less than 7 had a mortality rate of only 1.8%, whereas 61 attacks associated with a score greater than or equal to 7 had a mortality rate of 49%. The value of this scoring system needs to be confirmed in prospective studies, but it may prove useful, for example, in selecting a group of high-risk patients for urgent biliary decompression in an attempt to reduce the mortality associated with this pathology.