The susceptibilities of recent isolates of 30 coagulase-positive and 7 coagulase-negative staphylococci from the patients with chronic maxillary sinusitis were determined against each of 10 antimicrobial agents such as cloxacillin, cephaloridine, ampicillin, penicillin G, gentamicin, kanamycin, methicillin, erythromycin, sulbenicillin, oxytetracyclin. Cloxacillin was the most of all the agents tested against both coagulase positive and negative staphylococci and cephaloridine was more active than the other β-lactam antimicrobial agents, oxytetracycline was the most active and erythromycin was the least active. Methicillin resistant strains were also highly resistant to gentamicin and kanamycin although relatively susceptible to oxytetracycline. Coagulase negative strains were highly susceptible to all agents tested than coagulase positive strains.