The antimicrobial susceptibility of 339 isolates from the otorhinolaryngological infections at the otorhinolaryngological departments at 27 universities in Japan, as well as their 108 affiliated hospitals and practitioners during January 2007 to June 2007 was determined to garenoxacin (GRNX), levofloxacin, moxifloxacin, azithromycin, cefditoren, and cefcapene applicable for otorhinolaryngological infections. The in vitro activities of these drugs against the isolates were compared. The quinolones including GRNX were potently active against Streptococcus pneumoniae including penicillin-intermediate and -resistant strains (PISP and PRSP), Streptococcus pyogenes and methicillin-susceptible Staphylococcus aureus, except for MRSA, a major causative pathogens for otorhinolaryngological infection. When MIC ranges, MIC50, MIC80 and MIC90 of three quinolones were compared, it was considered that GRNX was the most active of them. GRNX was potently active against Haemophilus influenzae and Moraxella catarrhalis same as that of other quinolones tested. In conclusion, GRNX exhibits a potently active against fresh isolates from otorhinolaryngological infections, and has an effective potential in the treatment of otorhinolaryngological infections.