We tested in vitro the activities of streptomycin and tetracycline--antibiotics that have long been used to treat rhinoscleroma--as well as several newer oral agents by using 23 isolates of the causative organism Klebsiella rhinoscleromatis. All isolates were inhibited by clinically achievable concentrations of trimethoprim-sulfamethoxazole, amoxicillin-clavulanate, chloramphenicol, ciprofloxacin, cephalexin, cefuroxime, and cefpodoxime.