This volume contains 13 thoroughly refereed and revised papers detailing recent advances in research on trading agents, negotiating agents, dynamic pricing, and auctions. They were originally presented at the 10th International Workshop on Agent-Mediated Electronic Commerce (AMEC 2008) collocated with AAMAS 2008 in Estoril, Portugal, or the 6th Workshop on Trading Agent Design and Analysis (TADA 2008) collocated with AAAI 2008 in Chicago, IL, USA.The papers originating from AMEC 2008 address agent modeling and multi-agent problems in the context of e-negotiations and e-commerce. The TADA papers stem from the effort to design scenarios where trading agents and market designers can be pitched against each other in applications from supply chain management and procurement. They are all characterized by interdisciplinary research combining fields such as artificial intelligence, distributed systems, game theory, and economics.