To confirm the efficacy of the treatment regimen with oral levofloxacin (LVFX) 500 mg once daily for 7 days for patients with non-gonococcal urethritis (NGU), we evaluated the microbiological and clinical outcomes of the regimen in those patients. We finally evaluated 53 patients with symptomatic NGU and 5 patients with asymptomatic NGU. As a result of microbiological examinations, 19 of the symptomatic patients were diagnosed as having non-gonococcal chlamydial urethritis (NGCU); 13 had non-gonococcal non-chlamydial urethritis (NGNCU), and 21 had urethritis without any microbial detection. Five of the asymptomatic patients were diagnosed as having NGCU. Microbiological cure was achieved in 91% of the 32 patients with symptomatic NGU and in 80% of the 5 patients with asymptomatic NGCU. Clinical cure was obtained in 92% of the 53 patients with symptomatic NGU. The microbiological eradication rate for Chlamydia trachomatis was 92% in 24 patients. As for other organisms, the microbiological eradication rate for Mycoplasma genitalium was 60% in 5 patients and that for Ureaplasma urealyticum was 100% in 10. The microbiological and clinical efficacy of oral LVFX 500 mg once daily for 7 days for the patients with NGU was the same for the azithromycin (AZM) 1,000 mg single dose that we previously reported. The eradication rates of C. trachomatis and U. urealyticum in the treatment regimen with LVFX 500 mg were high enough in the clinical setting; however, for M. genitalium, the rate was relatively inferior to that with AZM.