In community-acquired pneumonia (CAP) the pathogenic microorganism is unknown at the time of diagnosis. For that reason the antimicrobial therapy is empirical, based in the clinical picture and the presumptive causal microorganisms. Hospitalization is one of the most important decisions in patients with CAP. Clinical criteria appropriate to identifying those patients requiring hospital admission for antimicrobial administration and clinical control must be defined. The stratification of patients according to the presence of risk factors such as age and co-morbidities permit to predict which are the potential pathogenic microorganisms and their adequate therapy. Trovafloxacin covers all the presumed bacterial spectrum, pharmacokinetics, easiness to be administered and to pass to the oral route, advantageous for all the groups under consideration. Patients older than 65 years of age or with co-morbidities and those that need to be hospitalized receive clear benefits from this antibiotic.