A multi-agent system is made up of multiple interacting autonomous agents. It can be viewed as a society in which each agent performs its activity cooperating to achieve common goals, or competing for them. They establish dialogues via some kind of agent-communication language, under some communication protocol. We think argumentation is suitable to model several kind of dialogues in multi-agents systems. In this paper we define dialogues and persuasion dialogues between two agents using Defeasible Logic Programs as a knowledge base, together with an algorithm defining how this dialogue may be engaged. We also show an indication of how an agent could use opponent’s information for its own benefit.Eje: AgentesRed de Universidades con Carreras en Informática (RedUNCI)