This volume contains the contributed papers and invited talks presented at the 1stInternationalWorkshoponAlgorithmicAspectsofWirelessSensorNetworks (ALGOSENSORS 2004), which was held July 16, 2004, in Turku, Finland, - located with the 31st International Colloquium on Automata, Languages, and Programming (ICALP 2004). Wireless ad hoc sensor networks have become a very important research subject due to their potential to provide diverse services in numerous appli- tions. The realization of sensor networks requires intensive technical research and development e?orts, especially in power-aware scalable wireless ad hoc c- munications protocols, due to their unusual application requirements and severe constraints. On the other hand, a solid theoretical background seems necessary for sensor networks to achieve their full potential. It is an algorithmic challenge to achieve e?cient and robust realizations of such large, highly dynamic, complex, n- conventional networking environments. Features, including the huge number of sensor devices involved, the severe power, computational and memory limi- tions, their dense deployment and frequent failures, pose new design, analysis and implementation challenges. This event is intended to provide a forum for researchers and practitioners to present their contributions related to all aspects of wireless sensor networks. Topics of interest for ALGOSENSORS 2004 were: – Modeling of speci?c sensor networks. – Methods for ad hoc deployment. – Algorithms for sensor localization and tracking of mobile users. – Dynamic sensor networks. – Hierarchical clustering architectures. – Attribute-based named networks. – Routing: implosion issues and resource management. – Communication protocols. – Media access control in sensor networks. – Simulators for sensor networks.