This is a randomized, open-label, parallel group, multicenter study to determine the safety and effectiveness of levofloxacin (488 mg once daily by mouth or 500 mg administered intravenously once daily for 7 - 14 days) compared with ceftriaxone sodium (1 - 2 grams administered into a vein or muscle once daily or in divided doses twice daily for 7 - 14 days) or cefuroxime axetil (500 mg by mouth twice daily for 7 - 14 days) in adults with community-acquired pneumonia. The study consists of 4 visits: one visit for screening and enrollment, and 3 visits for assessment of safety and effectiveness (one visit on Day 2 - 4 [on-therapy], one visit [post-therapy] 5 - 7 days after the last dose of the study drug, and one visit [post-study] 21 - 28 days after the last dose of the study drug). The total duration of patient participation in the study is approximately 6 weeks. Levofloxacin is an antibacterial agent used for the treatment of many types of infections in adults. The purpose of this study is to compare the safety and effectiveness of levofloxacin with other frequently used antibiotics (ceftriaxone sodium or cefuroxime axetil) in the treatment of adults with pneumonia acquired in the community. The primary efficacy assessment is the clinical response 5 - 7 days after the last dose of study drug, (categorized as cured, improved, or failed) based upon changes in signs and symptoms, and changes in x-ray findings, Safety evaluations (incidence of adverse events, physical examination, and laboratory tests) are performed throughout the study. Cost-effectiveness is also assessed for the study drugs. The study hypothesis is that treatment with levofloxacin will be at least as effective as ceftriaxone sodium or cefuroxime axetil in treating patients with pneumonia acquired in the community, and that it will be well tolerated. Levofloxacin 488 mg by mouth once daily or 500 mg intravenously once daily; ceftriaxone sodium (1 - 2 grams administered into a vein or muscle once daily or in divided doses twice daily); or cefuroxime axetil (500 mg by mouth twice daily). Treatment duration is 7 - 14 days.