Listeriosis usually affects immunocompromised patients including elderly people and pregnant women, but it may also affect otherwise healthy individuals. In our report, we present a case of a rare and very severe form of listeriosis-rhombencephalitis in a 61-year-old female with no history of immunosuppression, who, because of history, clinical picture, and laboratory results as well as negative cultures, was at first diagnosed with viral encephalitis. This paper underlines that Listeria monocytogenes infection should be taken into consideration in case of lymphocytic encephalitis even in immunocompetent patients. Typical MRI picture may be crucial in establishing a proper diagnosis as the lab results may be misleading.