Bacterial meningitis is an important cause of morbidity and mortality in the United States and throughout the world. The diagnosis of bacterial meningitis is often delayed in patients as a result of numerous factors such as length of illness, use of radiologic imaging studies, and/or prior use of antimicrobial agents. Many textbooks emphasize the need for prompt initiation of antimicrobial therapy in a patient with suspected acute bacterial meningitis to prevent many of the long-term sequelae associated with this disorder. We have reviewed the literature to determine if there is a standard of care for timing of administration of antimicrobial therapy in patients with a diagnosis of acute bacterial meningitis. Although the clinical data are inconclusive, it makes intuitive sense to initiate antimicrobial therapy as soon as possible in any patient with suspected or proven bacterial meningitis before the patient's illness advances to a high level of clinical severity, beyond which antimicrobial therapy is less likely to be of benefit. However, clinical experiences suggest that patient outcome in bacterial meningitis is a result of multiple factors, since some patients treated within a few hours of symptoms develop an adverse outcome whereas others who are symptomatic for days prior to presentation suffer no adverse sequelae.