In an open multicenter study [corrected], 112 male patients (mean age 47.1 years) with documented symptomatic chronic bacterial prostatitis were treated with oral temafloxacin 400 mg b.i.d. for 28 days. Urine and prostatic secretions were obtained for culture and susceptibility testing, and clinical signs and symptoms were evaluated at day 14 as well as 5-9 days and 26-30 days post-treatment. The most frequently isolated pretreatment pathogens (n = 97) were 36 strains (38%) of Escherichia coli and 16 strains (17%) of Enterococcus. Clinical success (cure plus improvement) was demonstrated in 74 of 81 (91%) patients at visit 4, 5-9 days post-treatment and at visit 5, 26-30 days post-treatment in 61 of 71 (86%) patients. At visit 4, 94% of patients had eradication of pretreatment pathogens. At visit 5, 92% had continued eradication of their original pathogens. Improvement was observed in the severity of signs and symptoms that existed pretreatment at visit 4 (visit 5): dysuria, 92% (93%); perineal pain, 95% (93%); lower abdominal pain, 93% (100%); lower back pain, 88% (93%); scrotal/penile pain, 91% (83%). Digestive system (6.3%) and nervous system (4.5%) adverse events were observed most frequently. Temafloxacin 400 mg b.i.d. administered orally for 28 days represents a safe and effective treatment for chronic bacterial prostatitis.