This volume constitutes the proceedings of the Third International Workshop on Rewriting Logic and its Applications.Following the successful first and second International Workshops on Rewriting Logic and its Applications, held in Asilomar (California) in September 1996 and in Pont-à-Mousson (France) in September 1998 respectively, the third workshop takes place in Kanazawa (Japan) in September 18, 19, 20 (Mon, Tue, Wed), 2000.Kanazawa is one of the most beautiful old towns in Japan. The workshop site (Kanazawa City Cultural Hall) is located just in the downtown of Kanazawa and major sightseeing spots are easily accessible on foot. This setting helps to make the workshop intimate, enjoyable, and productive.Rewriting logic is a natural semantic framework for concurrency, parallelism, and communication in computing, and for the specification of a wide range of systems and languages. It also has good properties as a logical framework for representing many varieties of logics. A growing number of research efforts exploring the foundations and applications of rewriting logic in all these directions are being carried out worldwide, and several languages based on rewriting logic such as CafeOBJ, ELAN, and Maude are being designed and implemented.The goal of WRLA2000 is to bring together researchers, from all over the world so that they can present their recent works, discuss future research directions, and exchange ideas. In addition to the presentations of research results, the program includes invited presentations and system demonstrations.Technical focuses of WRLA2000 are placed on such topics as secure protocol specifications and verification, future language features, rewriting for behavioral specifications, architecture for supporting system. We hope the discussions at the workshop help each participant to understand the current status and future issues of rewriting logic and relating fields.The workshop is supported by honest efforts of many people and organizations. The authors who submitted papers provide us the primary possibility of having interesting and productive workshop. The program committee members and external reviewers worked hard to review and select papers for presentation. These makes it possible for us to have an attractive program. The local arrangement and publicity chairs take care of running of the workshop, and let us enjoy the workshop under nice conditions. Ishikawa Prefecture, Kanazawa City, JAIST, SRA, and MRI support the workshop financially. We want to thank all of them for making it possible for us to have this productive workshop.Kanazawa, Japan, September 2000Kokichi Futatsugi