A new quinolone, zabofloxacin, has now been developed; hence, a non-inferiority trial is needed to compare this new compound with another widely used quinolone to examine its efficacy and safety for the treatment of chronic obstructive pulmonary disease (COPD) exacerbations. This was a prospective, multicenter, double-blind, double-dummy, randomized, controlled, parallel-group, Phase III, non-inferiority clinical trial designed to compare oral zabofloxacin (367 mg once daily for 5 days) with moxifloxacin (400 mg once daily for 7 days) for the treatment of patients with COPD exacerbation. In all, 345 COPD patients with a moderate COPD exacerbation were enrolled in the study via the outpatient clinics at 31 university hospitals. Clinical per protocol analysis revealed that the clinical cure rate for zabofloxacin was 86.7% and that for moxifloxacin was 86.3% (the rate difference, 0.4%; 95% confidence interval, −7.7%–8.6%). Intention-to-treat analysis revealed clinical cure rates of 77.1% and 77.3% (difference, −0.2%; 95% confidence interval, −9.0%–8.8%), respectively. These results confirm that zabofloxacin is not inferior to moxifloxacin. The favorable microbiological response rate for zabofloxacin was 67.4% and that for moxifloxacin was 79.5% (P=0.22). Patients in the zabofloxacin group showed better patient-oriented outcomes, as measured by EXAcerbations of Chronic Pulmonary Disease Tool-Patient-Reported Outcome and the COPD assessment test scores, than patients in the moxifloxacin group. Adverse drug reactions related to zabofloxacin occurred in 9.7% of cases and those related to moxifloxacin occurred in 9.6% of cases (P=0.97). The dropout rate due to adverse events was 0% (0/175) in the zabofloxacin group and 1.8% (3/167) in the moxifloxacin group (P=0.12). Oral zabofloxacin (367 mg once daily for 5 days) was not inferior to oral moxifloxacin (400 mg once daily for 7 days) for the treatment of patients with COPD exacerbation.