This volume contains the accepted papers from the 3rd International School andSymposium onAdvanced Distributed Systems heldin Guadalajara,Mexico, January24-30,2004.Thiseventwasorganizedbytheteamsmadeupofmembers of CINVESTAV Guadalajara, CUCEI, the Computer Science Department of the Centre of Research and Advances Studies at the CUCEA campus of the University of Guadalajara, Mexico, the University of Rostock, Germany and ITESO, Guadalajara. The ISSADS symposium provides a forum for scientists and people from industry to discuss the progress of applications and theory of distributedsystems.Thisyeartherewereover300participantsfrom3continents, among which about 20 percent came from industry. Theconferenceprogramconsistedof25acceptedpapersoutof46submissions and covered several aspects of distributed systems from hardware and system level up to di?erent applications. These papers were selected by a peer review process, in which each paper was evaluated by at least three members of the international program committee. Inaddition,thethreeinvitedspeakers,AdolfoGuzmanArenas,YakupParker and Joaquin Vila, presented interesting overviews to current development and research directions in distributed systems. Furthermore, eight tutorials and four industrial forums from IBM, INTEL, HP and SUN enabled the participants to extend their knowledge in selected areas. A panel, which was organized by a team composed of researchersfrom the Universidadde Guadalajaraand focused on tra?c control and simulation, also demonstrated the practical application of recent research in distributed systems to the problems of Guadalajara.