Conclusion: Moxifloxacin was generally well tolerated and highly effective in the treatment of acute bacterial rhinosinusitis (ABS). The incidence of adverse events (AEs) and adverse drug reactions (ADRs) was low. The effectiveness, safety, and tolerability information collected in this study confirm the clinical safety profile of moxifloxacin and its benefit as a treatment option for ABS. Objective: To assess the effectiveness, safety, and tolerability of moxifloxacin under daily life treatment conditions in patients with ABS. Methods: The study was carried out in China between September 2005 and May 2007. Patients with ABS were treated with moxifloxacin tablets 400 mg once daily for a duration that was left to the physician's discretion. Data were collected on demography, diagnosis of infection, pretreatment, concomitant diseases and medications, moxifloxacin therapy, course of symptoms during investigations, and final assessment of therapy. Results: In all, 578 patients with ABS treated with moxifloxacin were valid for effectiveness analysis. An improvement was observed in 98.8% (n = 571/578) of the patients. Cure was documented in 89.4% (n = 517/578) of the patients. The physicians' overall tolerability rating was 'very good' or 'good' in 92.9% (n = 537/578) of patients. The incidence rates of AEs and ADRs were 1.5% (n = 10/681) and 0.6% (n = 4/681), respectively. No serious AE was reported.