Nosocomial respiratory tract infections are the leading type of nosocomial infections. Despite the development of new antibiotic therapies, they are associated with an increased morbidity and mortality. Patients with comorbidities are especially predisposed to acquire these infections, as are patients exposed to respiratory therapy. Aspiration of colonized secretions from the oropharynx is the main mechanism of infection development. Barrier techniques to reduce aspiration and antimicrobial agents to alter bacterial flora are important in preventing pneumonia episodes. The initial institution of an adequate antibiotic regimen is a determinant of outcome. Nosocomial pneumonias are often difficult to treat due to antibiotic-resistant bacteria. Antibiotic policies are crucial in avoiding a progression in antibiotic resistance.