Listeria monocytogenes – intracellular Gram-positive bacterium of the Corynobacteriaceae family, is a pathogenic factor of listeriosis. Infection caused by this organism most commonly occurs by ingestion. In most cases, the disease is self-limiting, but may also occur in the form of sepsis, infections of the nervous system, local abscesses or infections of the gastrointestinal tract. Neuroinfections caused by L. monocytogenes are: meningitis, encephalitis and brain abscesses. An important component of listeriosis pathogenesis is to belong to a high-risk group of listeriosis which include, i.a. persons with weakened immune systems, infants, and pregnant women in whom the infection can lead to the miscarriages. We describe the case of 55-year-old woman admitted to the Intensive Care Unit in the Central Clinical Hospital in Katowice-Ligota with suspected encephalitis and sepsis of unknown etiology. On admission, the patient's condition was severe, she required intubation and ventilation by a respirator. During hospitalization, the doctors performed a lumbar puncture to examine the cerebrospinal fluid. The result of microbiological CSF examination directed a further course of therapeutic treatment to eradicate the infection of L. monocytogenes by antibiotic therapy. On the sixth day of treatment the patient was extubated. A gradual decrease in inflammatory parameters was observed during the patient`s stay in the ICU. This case illustrates the diagnostic process and the difficulties faced by the doctor treating the patient with meningitis caused by Listeria monocytogenes.