This volume contains the proceedings of DAIS 2013, the 13th IFIP International Conference on Distributed Applications and Interoperable Systems, sponsored by IFIP (International Federation for Information Processing) and organized by the IFIP Working Group 6.1. DAIS was held on June 3-6, 2013 in Florence, Italy, as part of the DisCoTec (Distributed Computing Techniques) federated conference, together with the International Conference on Formal Techniques for Distributed Systems (FMOODS and FORTE) and the International Conference on Coordination Models and Languages (COORDINATION). There were 42 submissions for DAIS. Each submission was reviewed by at least 3, and on the average 3.9, program committee members. The committee decided to accept 12 full papers and 6 short papers, giving an acceptance rate of 2% for full research papers. The conference program presented state-of-the-art research results and case studies in the area of distributed applications and interoperable systems. The main themes of this year's conference were cloud computing, replicated storage, and peer-to-peer computing. In the area of cloud computing, there are papers on security, adaptive replicated services, network forensics for the cloud, autnomously adapting applications, a benchmark-as-a-service, and building an ambient cloud for mobile ad-hoc networks. A significant number of the papers cover replicated storage, including providing SQL support for NoSQL databases, strengthening consistency for the Cassandra key-value store, using application-level knowledge to improve replication consistency models, improving transaction processing throughput for optimistic concurrency control through adaptive scheduling, and a study of the cost of consistency models in distributed filesystems. Two papers are on peer-to-peer computing, including algorithms for generating scale-free overlay topologies, and a model for a peer-to-peer-based virtual microscope. We also had papers on deploying experiments on smartphones, bandwidth prediction, asynchronous protocol gateways, and decentralised workflow scheduling. Finally, we would like to take this opportunity to thank the many people whose work made this conference possible. We wish to express our deepest gratitude to the authors of submitted papers, to all PC members for their active participation in the paper review process, and to all external reviewers for their help in evaluating submissions. We would like to thank the Steering Committee of DAIS, and in particular the chair Rui Oliviera for their advice and help. We would also like to thank Roberto Baldoni, our invited keynote speaker. Further thanks go to the University of Firenze for hosting the event in Florence, to the past DAIS Chairs Karl Göschka and Seif Haridi for their useful advice and documentation, and to Michele Loreti for acting as a General Chair of the joint event. April 4, 2013 Rennes, Stockholm Jim Dowling François Taïani