The level of knowledge of Listeria among mothers in Ireland is unknown. This prospective questionnaire study aims to evaluate the level of knowledge of recently delivered mothers regarding Listeria infection and its potential prevention. A response rate of 98% was achieved. A total of 271 (43.9%) mothers had heard about Listeria infection but only 187 (30.3%) knew that it was a food-borne pathogen. In total, 83 (13.5%) mothers recalled being told about Listeria infection by a midwife or doctor and 33 (5.3%) recalled receiving written information. A total of 224 (36.3%) of mothers were aware of the increased risk of listeriosis during pregnancy, while 250 (40.5%) knew the potential complications to the unborn fetus. A grand total of 505 (81.8%) mothers knew that they should avoid certain high-risk foods during pregnancy but 342 (55.4%) admitted to having consumed high-risk foods during their pregnancy. In conclusion, mothers' knowledge about listeriosis and its prevention was limited. Many mothers ate high-risk food during pregnancy. Antenatal advice regarding Listeria prevention needs to be improved.