A prospective, placebo controlled double-blind, randomised study comparing oral sparfloxacin 200 mg once daily following a 400 mg loading dose on day 1 with an oral combination of amoxycillin 1 g tid plus ofloxacin 200 mg bid was conducted in 211 hospitalised patients with community-acquired pneumonia. Patients were included in the study if they were aged > 65 years or had failed a previous course of antibacterial therapy. The duration of treatment was 10 days. The overall efficacy rates for the sparfloxacin and amoxycillin plus ofloxacin treatment groups were 91.9% and 81.5%, respectively, in evaluable patients at the end of treatment. Age or prior failure of antibacterial therapy did not affect the overall success rate of sparfloxacin. The safety profile of sparfloxacin was similar to that of the antibacterial combination. This study demonstrated that sparfloxacin given once daily is a suitable therapy for the treatment of community-acquired pneumonia in the elderly or in patients with failure of previous antibiotic therapy.