Listeria monocytogenes is ubiquitous in nature, being commonly present in faecal flora of otherwise healthy human population or animals. Clinical manifestation of listeria infection may vary widely from mild to invasive, life-threatening disease. In an immunocompromised host, a rather serious course should be expected. Due to cell-mediated immune insufficiency associated with pregnancy even a short bacteraemia in pregnant women can result in transplacental infection. Most listeria infections are sporadic but outbreaks may occur. An outbreak of listeriosis in the Czech Republic in the autumn of 2006 and winter of 2007 was associated with an increased incidence of perinatal listeriosis. More information on listeriosis prevention in pregnancy should be given and each febrile episode during pregnancy should be carefully examined. Early treatment of listeriosis reduces the risk of vertical transmission.