Nemonoxacin, a novel nonfluorinated quinolone, exhibits potent in vitro and in vivo activities against community-acquired pneumonia (CAP) pathogens, including multidrug-resistant Streptococcus pneumoniae. Patients with mild to moderate CAP (n = 265) were randomized to receive oral nemonoxacin (750 mg or 500 mg) or levofloxacin (500 mg) once daily for 7 days. Clinical responses were determined at the test-of-cure visit in intent-to-treat (ITT), clinical per protocol (PPc), evaluable-ITT, and evaluable-PPc populations. The clinical cure rates for 750 mg nemonoxacin, 500 mg nemonoxacin, and levofloxacin were 89.9%, 87.0%, and 91.1%, respectively, in the evaluable-ITT population; 91.7%, 87.7%, and 90.3%, respectively, in the evaluable-PPc population; 82.6%, 75.3%, and 80.0%, respectively, in the ITT population; and 83.5%, 78.0%, and 82.3%, respectively, in the PPc population. Noninferiority to levofloxacin was demonstrated in both the 750-mg and 500-mg nemonoxacin groups for the evaluable-ITT and evaluable-PPc populations, and also in the 750 mg nemonoxacin group for the ITT and PPc populations. Overall bacteriological success rates were high for all treatment groups in the evaluable-bacteriological ITT population (90.2% in the 750 mg nemonoxacin group, 84.8% in the 500 mg nemonoxacin group, and 92.0% in the levofloxacin group). All three treatments were well tolerated, and no drug-related serious adverse events were observed. Overall, oral nemonoxacin (both 750 mg and 500 mg) administered for 7 days resulted in high clinical and bacteriological success rates in CAP patients. Further, good tolerability and excellent activity against common causative pathogens were demonstrated. Nemonoxacin (750 mg and 500 mg) once daily is as effective and safe as levofloxacin (500 mg) once daily for the treatment of CAP.