Adding vancomycin to the antibiotic regimen is recommended for the treatment of pneumococcal meningitis in adults. Use of dexamethasone as adjunct therapy has proved to reduce mortality and neurologic sequelae in adult patients with pneumococcal meningitis. However, use of dexamethasone may impair penetration of vancomycin in cerebrospinal fluid. In a purely observational manner, we thought to measure blood and CSF concentrations of vancomycin in adult patients with pneumococcal meningitis, treated with vancomycin, third-generation cephalosporin and dexamethasone.