The Infectious Diseases Unit of Lucca Hospital conducted a multicentric retrospective study to evaluate the epidemiological and clinical features of adult patients affected by bacterial meningitis attending all the Infectious Diseases Units of Tuscany (Italy) from July 1999 to June 2004. A specific questionnaire was sent to all the units to collect information about each case of bacterial meningitis occurring in patients older than sixteen. Patients with meningitis by Mycobacterium tuberculosis were excluded from the analysis. Nine out of 12 Infectious Diseases Units of Tuscany took part in the study and 197 cases were identified. Most cases of meningitis occurred during 2002 with a slight reduction in cases in subsequent years. Streptococcus pneumoniae and Neisseria meningitidis were the most frequently isolated pathogens with an increase in diagnosis from 1999 to 2004; in 23.8% of patients no pathogens were isolated, with a reduction in meningitis from unknown aetiology from 1999 to 2004. Most patients were treated with a combination of two antibiotics, and corticosteroid drugs were added to the therapy; in the group of patients treated with corticosteroid drugs invalidating complications occurred in 23% of cases and 5% of patients died. In all, 27 out of 197 subjects (13.7%) developed invalidating complications and 20 out of 197 patients (10.2%) died.