This paper presents a multi-agent model, ECAS, for sequencing a mixed-model assembly line. ECAS implements the concept of deliberative and cooperative agents: the agents contract in order to fmd a solution which overcomes the objectives of the single agents in order to pursue the global optimum of the system. ECAS represents the extension of a previous model by the author, AGENT, which implements deliberative but not cooperative agents. One of the aims of this paper is to compare the results of the two models in order to evaluate the value added by cooperation. Moreover, ECAS performance is compared with other traditional approaches to the same problem.