Antimicrobial susceptibility of the bacterial strains isolated from clinical specimens during the period from June, 1983 to June, 1986 in Yeungnam Medical Center was studied and the following results were obtained. 1. Staphylococcus aureus was highly susceptible to cephalothin and its susceptibility to methicillin was gradually reduced. 2. Streptococcus strains except enterococcus were generally susceptible to penicillin, while most enterococci were susceptible to only ampicillin. 3. Gram-negative rods including Escherichia coli were highly susceptible to amikacin and tobramycin. 4. Serratia were generally less susceptible to the amtimicrobials tested than other Enterobacteriaceae. Among them, Serratia marcescens showed the highest susceptibility to amikacin and chloramphenicol. 5. Pseudomonas aeruginosa revealed the highest susceptibility to amikacin and tobramycin and moderate susceptibility to carbenicillin and gentamycin. 6. Acinetobacter calcoaceticus revealed low susceptibility to most antimicrobials tested, showing only 30% susceptibility to amikacin, tobramycin and gentamycin in 1986.