This book constitutes the refereed proceedings of the First International Workshop on Mobility Aware Technologies and Applications, MATA 2004, held in Florianopolis, Brazil in October 2004. The 35 revised full papers presented together with one invited paper were carefully reviewed and selected from numerous submissions. The papers are organized in topical sections on context-aware support for mobile systems, context-aware applications and networks, service and network management, grid and agent technologies in mobile environments, sensor networks, security issues, performance and QoS, mobility-aware systems and services, and agent technology and applications.