Pneumonia is an important cause of morbidity and mortality. A variety of conditions that damage the airways and weaken host defense mechanisms increase the susceptibility of the individual to bacterial colonization of the pulmonary tree. Because the clinician frequently cannot determine the etiologic agent, pneumonia is often treated empirically. Cefonicid, a long-acting cephalosporin, is a useful and cost-effective antibiotic that is active against many of the common pathogens that cause community-acquired pneumonia, such as Streptococcus pneumoniae and Haemophilus influenzae. It is also active against less common community-acquired pathogens, such as Klebsiella pneumoniae, Escherichia coli, and some anaerobic mouth flora. Erythromycin is useful when Mycoplasma or Legionella species are suspected. Cefonicid's demonstrated safety and efficacy, its low cost, and its long half-life, permitting once-daily dosing, make this antibiotic an ideal parenteral choice for empiric therapy of community-acquired pneumonia.