Eligible patients were randomised in this multicentre, randomised, double-blind, double-dummy parallel-group study in a ratio of 1:1 to either gatifloxacin 400 mg once-daily for 5–14 days plus matching placebo, or clarithromycin 500 mg twice-daily for 5–14 days. The primary outcome measure was clinical response (clinical cure plus improvement) at the end of treatment. Secondary endpoints were clinical response at end of study, clinical cure at end of treatment and end of study, bacteriological response at end of treatment and end of study, and treatment duration. The overall clinical response was similar in the two treatment groups, with 92.2% of gatifloxacin-treated patients cured or improved at the end of treatment, compared with 93.1% of those receiving clarithromycin. Corresponding bacteriological response rates (eradication plus presumed eradication) were 96.7% and 87.5%, respectively. The study drugs were well-tolerated, with nausea (gatifloxacin) and bitter taste (clarithromycin) being the only treatment-related adverse events with a frequency of > 5%. No patients experienced phototoxicity, hepatic or renal dysfunction, tendonitis or crystalluria. Oral gatifloxacin 400 mg once-daily appeared to be a safe and effective alternative to clarithromycin in the treatment of community-acquired pneumonia.