The aim of this study was to confirm further the efficacy and safety of levofloxacin in patients with chronic bacterial prostatitis (CBP) in Europe. Men with a history of CBP were enrolled in a prospective, multinational (eight countries), open-label study to receive levofloxacin 500 mg once daily per os (p.o.) for 28 days. Patients were followed for 6 months. A total of 117 patients were treated. Gram-negative bacteria were identified in 57/106 patients (mainly Escherichia coli (n=37)) and Gram-positive bacteria in 60/106 patients (mainly Enterococcus faecalis (n=18) and Staphylococcus epidermidis (n=14)). Among the intention-to-treat population (n=116), the clinical success rate (cured and improved patients) was 92% (95% confidence interval (CI) 84.8-96.5%), 77.4% (95% CI 68.2-84.9%), 66.0% (95% CI 56.2-75.0%) and 61.9% (95% CI 51.9-71.2%) at 5-12 days, 1 month, 3 months and 6 months post treatment. The microbiological eradication rate according to evaluation scheme II was 82/98 (83.7%, 95% CI 74.8-90.4%) at 1 month and the continued eradication rate was 52/57 (91.2%, 95% CI 80.7-97.1%) at 6 months post treatment. Comparison of four classification schemes showed similar results. Thus, the present investigation is suitably comparable in methods and results to previous studies. Levofloxacin was well tolerated. Four patients (3.4%) discontinued therapy due to adverse events and 15 patients (12.8%) experienced at least one adverse event. Levofloxacin 500 mg p.o. once daily for 28 days is clinically and microbiologically effective in the treatment of CBP caused by susceptible pathogens and is well tolerated.