Background: The Tokyo Guidelines for the management of acute cholangitis and cholecystitis were published in 2007 (TG07) and have been widely cited in the world literature. Because of new information that has been published since 2007, we organized the Tokyo Guidelines Revision Committee to conduct a multicenter analysis to develop the updated Tokyo Guidelines (TG13). Methods/materials: We retrospectively analyzed 1,432 biliary disease cases where acute cholangitis was suspected. The cases were collected from multiple tertiary care centers in Japan. The 'gold standard' for acute cholangitis in this study was that one of the three following conditions was present: (1) purulent bile was observed; (2) clinical remission following bile duct drainage; or (3) remission was achieved by antibacterial therapy alone, in patients in whom the only site of infection was the biliary tree. Comparisons were made for the validity of each diagnostic criterion among TG13, TG07 and Charcot's triad. Results The major changes in diagnostic criteria of TG07 were re-arrangement of the diagnostic items and exclusion of abdominal pain from the diagnostic list. The sensitivity improved from 82.8% (TG07) to 91.8% (TG13). While the specificity was similar to TG07, the false positive rate in cases of acute cholecystitis was reduced from 15.5 to 5.9%. The sensitivity of Charcot's triad was only 26.4% but the specificity was 95.6%. However, the false positive rate in cases of acute cholecystitis was 11.9% and not negligible. As for severity grading, Grade II (moderate) acute cholangitis is defined as being associated with any two of the significant prognostic factors which were derived from evidence presented recently in the literature. The factors chosen allow severity assessment to be performed soon after diagnosis of acute cholangitis. Conclusion: TG13 present a new standard for the diagnosis, severity grading, and management of acute cholangitis.