This book constitutes the refereed proceedings of the 5th Hellenic Conference on Artificial Intelligence, SETN 2008, held at Syros, Greece in October 2008.The 27 revised full papers together with 17 revised short papers were carefully reviewed and selected from 76 submissions. The papers address any area of artificial intelligence; particular fields of interest include: Adaptive Systems, AI and Creativity, AI rchitectures, Artificial Life,Autonomous Systems, Data Mining and Knowledge Discovery, Hybrid Intelligent Systems and Methods, Intelligent Agents, Multi-agent Systems, Intelligent Distributed Systems, Intelligent Information Retrieval, Intelligent/Natural Interactivity, Intelligent Virtual Environments, Knowledge Representation and Reasoning, Logic Programming, Knowledge-Based Systems, Machine Learning, Neural Nets, Genetic Algorithms, Natural Language Processing, Planning and Scheduling, Problem Solving, Constraint Satisfaction, Robotics, Machine Vision, Machine Sensing.