The management of hospital-acquired pneumonia (HAP) presents a major challenge for the clinician. The insensitivity of current diagnostic methods and the increasing prevalence of nosocomial pathogens with multiple antibiotic resistance complicate the issue. Use of mechanical veritilation and broad-spectrum antimicrobials in the intensive care setting predipose patients to acquire HAP more frequently with antimicrobial - resistant pathogens. Controversy exists regarding the patients in which invasive diagnostic testing is indicated; the timing of these procedures is another subject of debate. Proper empirical therapy, is fundamental to a favourable outcome, and the selection of inappropriate agents to which pathogens are resistant contributes significantly to morbidity and mortality. In general, there is agreement on the requirement for a thorough knowledge of the local causative organisms and the pathogens' resistance profiles. A wide variety of antimicrobials can be used either as monotherapy or in combinations. (C) 2002 The Hospital Infection Society.