Although the pharmacokinetics of ceftriaxone allows its administration in a single daily dose, this practice is not standard in the treatment of bacterial meningitis. Herein, we review our experience and that of other investigators with this mode of therapy. We used a single daily dose of ceftriaxone (50 mg/[kg.d]; maximum, 4 g/d) for the treatment of bacterial meningitis in 84 adult patients. Meningitis was due to Neisseria meningitidis in 34 cases, to Streptococcus pneumoniae in 25, to Escherichia coli in three, to Klebsiella pneumoniae in two, to Haemophilus influenzae in two, to viridans streptococci in two, and to an unknown agent in 16. Eleven patients died, for an overall mortality of 13%; therapy failed in three additional cases. The mean trough levels of ceftriaxone in cerebrospinal fluid was 3.5 micrograms/mL; the median trough bactericidal titer at this site was 1:128. Both our experience and that in the literature suggest that a single daily dose is optimal when ceftriaxone is used for the treatment of bacterial meningitis.