Nowadays multi-agents has established as one of the most important areas of research and development in information technology. Agents are normally involved in cooperative distributed problem and they face frequently with incomplete and/or conflicting information or task. Since more and more concern is attached to agents’ teamwork and agents’ dialogue, conflicts naturally arise as a key issue to be dealt with, not only with application dedicated techniques, but also with more formal and generic tools. In this semi-expository paper we show that a formal treatment for multi-agent knowledge representation that can represent conflicts and incomplete information is possible through new logical system, namely the paraconsistente logics. We discuss one of such system adding suitable modal operators for knowledge.