This volume contains the papers presented at the Fifth International Workshop on Database Machines. The papers cover a wide spectrum of topics on Database Machines and Knowledge Base Machines. Reports of major projects, ECRC, MCC, and ICOT are included. Topics on DBM cover new database machine architectures based on vector processing and hypercube parallel processing, VLSI oriented architecture, filter processor, sorting machine, concurrency control mechanism for DBM, main memory database, interconnection network for DBM, and performance evaluation. In this workshop much more attention was given to knowledge base management as compared to the previous four workshops. Many papers discuss deductive database processing. Architectures for semantic network, prolog, and production system were also proposed. We would like to express our deep thanks to all those who contributed to the success of the workshop. We would also like to express our apprecia­ tion for the valuable suggestions given to us by Prof. D. K. Hsiao, Prof. D.