The polymerase chain reaction (PCR) is considered the most reliable method for the rapid identification of Listeria monocytogenes in foods, when a response within 24 h is needed; however, with this method false reactions caused by the abundant DNA present in the food extract are possible. DNA probes are less sensitive than PCR, but they can be very useful for confirming the doubtful cases obtained with the PCR or for the identification of isolated and purified strains. The use of PCR in combination with a specific DNA probe can be the best method for obtaining a rapid, sensitive and reliable identification of Listeria within a working day or less.