The history and findings of all patients with Listeria meningitis admitted to the University Hospital of Leuven from 1967 to 1987 were reviewed. Listeriosis during pregnancy or the perinatal natal period was not considered. Predisposing conditions in these 23 patients included renal transplants (9), immunosuppressive therapy (2), diseases of the lympthoreticular system (3) and chronic alcoholism (1). One man had an inversed T4/T8 ratio. In 7 patients no underlying disorder was detected. Disease onset may be acute or subacute. There are no clinical features distinguishing Listeria meningitis from other acute bacterial meningitides. The number of leukocytes in the CSF varied from 3 to 3700, most often with a predominance of mononuclear cells. A decrease of the glucose level in the CSF was not always present. The initial gram stain was often unrevealing and it took up to 4 days for CSF cultures to become positive. Blood cultures were often important for the identification of the organism.