Automated negotiation by autonomous agents has become increasingly important since the advent of e-marketplace. In this study, automated negotiation is viewed as a search process in which negotiators jointly search for a mutually acceptable contract in a multidimensional space formed by negotiable issues. This search is formulated as a multiple-objective decision making problem and is solved through an iterative process of generating offers by fuzzy inference systems. These fuzzy inference systems serve as a search heuristic and are formulated based on the strategy of issue trade-offs. Five experiments are conducted to evaluate the performance of the proposed automated negotiation algorithm.