Listeria monocytogenes is an infectious disease agent not seen frequently in the public. Nevertheless, it can lead to life-threatening infections in some special patient groups. The aim of this study was to draw attention to the rarely seen agent in a L. monocytogenes-induced meningitis case, whose primary isolation had been reported as Corynebacterium spp. A 67-year-old female patient applied to the emergency service with clouding of consciousness and speech impediment, and her fever was found 37.7°C. Though the patient was conscious, her orientation and cooperation was weak. Neck rigidity was present. No other pathological finding was detected. Her laboratory results were as follows: leucocyte 10.800/mm3 and CRP 188 mg/dL. In her cerebrospinal fluid examination, leucocyte was 900/ mm3, protein 552 mg/dL, glucose 0 (blood glucose 150 mg/dL). Cerebrospinal fluid culture determined Corynobacterium spp. on the second day of incubation. The laboratory was warned for Listeria. After further examination, cerebrospinal fluid culture was concluded as L. monocytogenes. The agent was also isolated from the patient’s blood. The patient was discharged uneventfully upon completing a three-week treatment. L. monocytogenes-related central nervous system (CNS) involvement develops secondary to bacteremia and manifests itself most commonly with meningitis. Bacteremia accompanied the clinical picture of our patient, as well. It has been reported that while blood cultures are found positive in the early period in 60-75% of the patients with CNS involvement, cerebrospinal fluid cultures are found positive in the late period. Agent could not be shown in cerebrospinal fluid Gram staining in 60-70% of the patients. Microorganism could not be determined in cerebrospinal fluid staining of our patient. We were informed about suspected contamination and that there was a diphtheroid image on the Gram staining of the cerebrospinal fluid culture. After further examination was conducted following our warning, the bacteria that grew was defined as L. monocytogenes. Treatment period in Listeria meningitis depends on the patient and infection type, and the optimal duration is unknown. An underlying immunodeficiency was not detected in our patient. Treatment durations recommended in healthy cases for Listeria infection are 21 days in meningitis, 14 days in bacteremia, and at least 6 weeks in brain abscess. Therefore, through this case, it was our intention to emphasize that Listeria should be considered when diphtheroids are reported in blood and cerebrospinal fluid cultures and that empirical treatment should be started pointblank in line with the recommendations for age groups when meningitis cannot be excluded.