PEDro is a database of clinical trials designed to assist the practice of evidence-based physiotherapy. When complete, it will contain bibliographic details, abstracts and quality assessment scores of all published randomised controlled trials in physiotherapy. Trials on the database will be rated on the basis of their methodological quality, so that users of the database can be guided to those trials which provide the most methodologically sound sources of evidence. The database has been made freely available on the world wide web, where it can be searched with a powerful and user-friendly search engine.