This book constitutes the proceedings of the 19th IFIP International Conference on Distributed Applications and Interoperable Systems, DAIS 2019, held in Kongens Lyngby, Denmark, in June 2019, as part of the 14th International Federated Conference on Distributed Computing Techniques, DisCoTec 2019. The 9 full papers presented together with 2 short papers were carefully reviewed and selected from 28 submissions. The papers addressed challenges in multiple application areas, such as the Internet-of-Things, cloud and edge computing, and mobile systems. Some papers focused on middleware for managing concurrency and consistency in distributed systems, including data replication and transactions.