A systematic review of references conducted in the process of developing the Guidelines for the Management of Acute Cholangitis and Cholecystitis did not find many high-quality research reports. There were no criteria for diagnosis, severity assessment, or patient transfer, and no established principles of clinical practice guidelines for acute cholangitis and cholecystitis. In order to develop guidelines that would be useful in clinical practice, an understanding of the current status of clinical practice for acute cholangitis and cholecystitis was considered essential. After several open symposia and a survey of these two diseases, we developed and published a Japanese-language version of Evidence-Based Practice Guidelines for the Management of Acute Cholangitis and Cholecystitis. In order to prepare international Guidelines, we had repeated discussions about the draft Guidelines together with international experts, and, following the Consensus Meeting, held on April 1-2, 2006, in Tokyo, with the attendance of 300 world experts in the field, the International Guidelines for the Management of Acute Cholangitis and Cholecystitis were developed. In this article, we outline the comments and opinions given at the International Meeting and how they are reflected in the final version of the Guidelines.