Listeria monocytogenes is an intracellular bacterium responsible for a disease characterized by several clinical features, such as septicemia, brain infection, abortion, and perinatal infection. These clinical features are attributed to its amazing capacity to cross several barriers in susceptible hosts. Intracellular infection is a consequence of the bacterium's capacity to enter a wide variety of mammalian cells, to not only survive but also replicate therein, and to its faculty to spread from one cell to the next, thereby escaping the humoral immune response. Here, we review both the well-established and the newly discovered strategies used by this bacterium to achieve this intracellular lifestyle while escaping from the host innate immune response. More than ever, Listeria appears as a model system and a reference in infection biology. © 2011 John Wiley & Sons A/S.