This book constitutes the reviewed proceedings of the First International Workshop on Algorithmic Aspects of Wireless Sensor Networks, ALGOSENSORS 2004, held in Turku, Finland in July 2004, in association with ICALP 2004. The 15 revised full papers presented together with abstracts of two invited papers were carefully reviewed and selected from 40 submissions. Among the topics addressed are sensor network modeling, algorithms for sensor localization, dynamic sensor networks, sensor network architectures, attribute-based named networks, routing, communication protocols, access control in sensor networks, sensor architecture, and energy consumption issues.