A trial in which patients over 18 years of age who are hospitalized with community acquired pneumonia and are otherwise eligible for entry into the study are randomly selected to receive one of two treatment regimens. After written informed consent is obtained, patients will receive one of the following two treatment regimens: 1) intravenous administration of azithromycin and ceftriaxone followed by azithromycin tablets, or 2) intravenous administration of levofloxacin followed by levofloxacin tablets. At least four study visits are normally conducted up to approximately one month after starting therapy. The objective of this study is to compare the safety and efficacy of the two treatment regimens.