The in vitro activities of 16 antimicrobial agents against 86 strains of Corynebacterium striatum were evaluated by microdilution using cation-adjusted Mueller-Hinton broth. MICs at which 90% of strains were inhibited were 0.06 microgram/ml for teicoplanin, 1 microgram/ml for vancomycin, 0.03 to 8 micrograms/ml for beta-lactams, 8 micrograms/ml for sparfloxacin, 16 micrograms/ml for ciprofloxacin, 16/304 micrograms/ml for co-trimoxazole (trimethoprim-sulfamethoxazole), 64 micrograms/ml for tetracycline, 128 micrograms/ml for gentamicin, and > 128 micrograms/ml for amikacin, erythromycin, and rifampin.