Two hundred and thirty six samples of raw milk were collected from bulk milk cans and tanks of individual dairy farms at El-Behera and
27(11.4%) of 236 Alexandria Governorates. Listeria was isolated from examined samples. The incidence of Listeria monocytogenes was 3% (7/236), while 8.5% (20/236) of raw milk samples were contaminated with L.innocua. The Listeria monocytogenes isolates were identified
serologically by using Bacto Listeria "O" antisera Type 1 & 4. Experi mental inoculation of L.monocytogenes into a white mice proved that the organism infect mice, replacing within the tissues and organs and lead to death. Histopathological examination for the liver and brain of sacrified mice revealed that the early macroscopic jesion appeared in the form of haemorrhagic foci and late lesion showed necrosis which started after the fourth day of inoculation and became prominant after the fifth day until death. The public health importance of the organism as well as the suggested measures for improving the quality of milk are discussed.