This article evaluates the impact of the ICH E9 guideline Statistical Principles for Clinical Trials on the conduct of clinical trials in Japan. In particular, the following Japanese practices in the conduct of clinical trials are discussed in detail from the ethical, statistical, and logical viewpoints: 1. Conducting only one phase 3 multicenter trial with many centers and few subjects per center; 2. Seeking to show noninferiority to an active control rather than superiority to placebo; and 3. Choosing a global assessment variable with a subjective component as the primary endpoint. The influence of public health insurance and the potential number of patients in Japan on various aspects of a trial are discussed. Problems requiring further research are mentioned and points requiring clarification are highlighted. © 2003, Drug Information Association. All rights reserved.