A variety of antibiotics is available to physicians caring for the pulmonary patient. New antimicrobial agents are continually being introduced, and an understanding of these new drugs is necessary if one hopes to make effective antibiotic choices. Our review focuses on two groups of agents that have been released recently: (a) those used primarily in hospitalized patients, and (b) those having a role in the outpatient setting. Drugs in the first group include imipenem-cilastatin, the parenteral fluoroquinolones, and the monobactams. Antibiotics in the second category include the new macrolides and azalides, the oral quinolones, the new oral cephalosporins, and the carbacephems. The pharmacokinetic properties, spectrum of activity, and safety profile of these agents serve as the basis for establishing their role in the therapy of pulmonary infections. This information should assist the clinician in deciding when these antibiotics offer advantages over older and frequently less expensive antimicrobial agents.