Abstract: Metastable states are very common in nature and are typical of systems close to a first order phase transition. Classical examples are the supersaturated vapor and the magnetic hysteresis. The full mathematical description of metastability is quite recent and still incomplete. In this framework, Probabilistic Cellular Automata pose challenging problems and show unexpected behaviors. In this talk we study the metastability properties of a class of PCA with multiple (not necessarily degenerate) metastable states.