isteria monocytogenes is a gram positive aerobic bacterium invading macrophages and epithelium and it enters the body via gut following ingestion of contaminated foods. Besides the virulence of the bacteria, cellular immunity is also important for defense against this microorganism. It usually causes a mild gastroenteritis but rarely meningitis in healthy people.1 Life threatening bacteriemia and meningitis caused by L. monocytogenes are generally seen in newborns, geriatric population and immunosuppressive patients including organ recipients. 2,3 We presented a patient with meningitis due to L. monocytogenes after allogeneic BMT, a rarely reported case in the literature. A AB BS S T TR RA AC CT T Viral, fungal and bacterial infections are commonly seen in patients early after the allogeneic bone marrow transplantation (BMT), because of neutropenia in the early period, later they occur due to cell mediated immune deficiency and at the late post transplant period due to immunoglobulin deficiency. Listeria monocytogenes is a gram positive bacterium that invades and proliferates in macrophages and epithelium. Because it is an intracellular bacterium, besides its virulence, host immune system is also important for defence mechanism against bacterium. Life threatening bacteriemia and meningitis caused by L. monocytogenes are generally seen in newborns, elderly and immunosuppressive patients including organ recipients. Herein we reported a patient who had allogeneic BMT due to myelodysplastic syndrome-refractory anemia with excess blasts (MDS-RAEB), presented with L. monocytogenes meningitis six months after allogeneic transplantation.K Ke ey y W Wo or rd ds s: : Bone marrow transplantation; immunosuppression; meningitis, listeria Ö ÖZ ZE ET T Allogeneik kök hücre nakli sonrası akut dönemde nötropeni, daha sonra hücresel immun yetmezlik ve son dönemde de hipogamaglobulinemi nedeniyle viral, fungal ve bakteriyel enfeksiyonlara sık rastlanmaktadır. Listeria monocytogenes makrofaj ve epitel hücrelerine yerleşen gram pozitif bir bakteridir. Hücre içinde çoğalması nedeniyle konak savunmasında bakterinin virü-lansının yanısıra konağın bağışıklık sistemi de önemlidir. Hayatı tehdit edici L. monocytogenes infeksiyonlarına ve menenjite özellikle yeni doğan, yaşlılar ve organ nakli yapılmış hastalar da dahil olmak üzere immün sistemi baskılanmış kişilerde sık rastlanmaktadır. Burada, nadir görülmesi nedeniyle, miyelodisplastik sendrom-aşırı blastlı refrakter anemi (MDS-RAEB) tanısı ile allogeneik kemik iliği nakli yapıldıktan altı ay sonra menenjit tablosu ile başvuran ve etken olarak L. monocytogenes gösterilen bir olgu sunduk.