Given the frequent topology changes in Mobile Ad Hoc Networks (MANET), the choice of appropriate broadcasting techniques is crucial to ensure reliable delivery of messages. The spreading of broadcast messages has a strong similarity with the spreading of infectious diseases. Applying epidemiological models to broadcasting allows an easy evaluation of such strategies depending on the MANET characteristics, e.g. the node density. In this paper, we develop an epidemic model for gossiping, which is a flooding-based probabilistic broadcasting technique. We analytically investigate the impact of node density and forwarding probability on the quality of gossiping. The result of our investigation is to enable mobile nodes for dynamically adapting their forwarding probability depending on the local node density. Simulation results in ns-2 show the reliability, efficiency and scalability of adaptive gossiping. Key words: MANET, Broadcasting, Gossiping, Reliability, Epidemic Models, Analytical ...