Infectious aneurysms represent <
5 % of cases [1] with a crucial and challenging diagnosis. Staphylococcus, Streptococcus, Enterobacteria are mostly involved but unusual pathogens like Listeria monocytogenes can be responsible. Collecting data of these rare situations allows to improve diagnosis. We report a case of L. monocytogenes aortic aneurysm, at a departmental hospital, in a 77-year-old immunocompetent patient without endovascular material, with an antecedent of colorectal carcinoma in remission and alcoholism, and compared it with literature data. Blood cultures were negative but culture of aortic tissues was positive. Only 19 similarly cases were identified since 1965. Infectious aneurysm represents a serious condition with a difficult diagnosis needing multiple approaches. When an infection is suspected, collection of blood culture and tissue of the aortic wall are needed as well as biomolecular and serological tools for exigent pathogens.