Thirty-six patients with Lyme meningitis diagnosed at the Department of Infectious Diseases, University Medical Centre, Ljubljana in 1993 and 1994 were enrolled in a prospective study. All patients had lymphocytic meningitis, negative serum IgM antibody titres to tick-borne encephalitis virus and met at least one of the following four criteria: i) isolation of Borrelia burgdorferi sensu lato from cerebrospinal fluid (2 patients), ii) intrathecal borrelial antibody production (22 patients) iii) seroconversion to borrelial antigens (3 patients) and/or iv) erythema migrans in the period of four months prior to the onset of neurological involvement (21 patients). All patients underwent antibiotic treatment and were followed up for one year. The results of our study revealed that Lyme meningitis frequently occurs without meningeal signs and is often accompanied by additional neurological and/or other manifestations of Lyme borreliosis. During the first year after antibiotic treatment, minor and major manifestations of Lyme borreliosis persisted or occurred for the first time in several patients. They were not infrequent even at the examination performed one year after therapy.