Two cases of perinatal listeriosis are reported by the Authors. The Authors emphasize that in Italy the incidence of this disease is undervalued. Additionally, the pregnant woman comes to be affected by forms which do not clinically fall within standard levels and whose course does not get worse over a certain limit. On the other hand, the fetus suffers substantial damages like abortion, premature labour with its subsequent failure or in case with a fetus affected by listeriosis. Two main clinical forms do exist in the neonatal period: the early form that is the septicemic form and the later form that is the meningitic form. As regards therapy on newborn, the Authors report that a mixture of Ampicillin and Aminoglycosides turns out to be successful for recovering patients from listeriosis. Furthermore, the Ampicillin together with a general igienic therapy are a good protection for the fetus and newborn in a pregnant woman.