Traditional East Asian medicines, Kampo included, are to be incorporated into International Classification of Diseases11 (ICD-11) which will be released in2015.To understand the significance of this plan, ICD itself needs to be understood. In this article, we describe ICD history, its significance and problems, and why the WHO became interested in traditional medicine. In the beginning, the ICD was only for classifying causes of mortality, and has since expanded to cover disease information according to the diverse needs of a changing society. And in Japan today, it is widely used not only for death certificate and disease information, but also for research purposes. There are many problems with the ICD, however:e.g. it is not clinically convenient, and it lacks certain terminology. Revision from IDC-10 to ICD-11 is now ongoing. It will be expanded and electronic. At the same time, plans are to have it broadly implemented in Asia by including traditional East Asian medicine.