Negotiation plays a fundamental role in e-commerce. In this paper, the application of defeasible logic for automated negotiation is investigated. Defeasible logic is flexible enough to be adapted to several possible negotiation strategies, has efficient implementations, and provides a formal basis for analysis (e.g. to explain why a negotiation was not successful). Two case studies, one small and one more comprehensive, will be described and the feasibility of approaches based on defeasible logic will be discussed
