Background The international practice guidelines for patients with acute cholangitis and cholecystitis were released in 2007 (TG07) and revised in 2013 (TG13). This study investigated updated epidemiology and outcomes among patients with acute cholangitis on a larger scale for the first time. Methods This is an international multi-center retrospective observational study in Japan and Taiwan. All consecutive patients older than 18 years of age and given a clinical diagnosis of acute cholangitis by clinicians between 1 January 2011 and 31 December 2012 were enrolled. Those who met the diagnostic criteria of acute cholangitis by TG13 were statistically analyzed. Results A total of 7,294 patients were enrolled and 6,433 patients met the TG13 diagnostic criteria. The severity distribution was Grade I (37.5%), Grade II (36.2%), and Grade III (26.2%). The 30-day all-cause mortality was 2.4%, 4.7%, and 8.4% in Grade I, II, III severity, respectively (P < 0.001). The incidence of liver abscess and endocarditis as complications of acute cholangitis was 2.0% and 0.26%, respectively. Conclusions This is the first large scale study to investigate patients with acute cholangitis. This study provides the basis to define the best practices to manage patients with acute cholangitis in future studies.