This study was designed to determine the bacterial susceptibility of non-fermentative Gram-negative organisms to various antibacterial agents. Bacterial susceptibility testing used the Kirby-Bauer method and data were assessed according to NCCLS 2000. Cefoperazone/sulbactam (CPER/SU) had good antibacterial activity against Pseudomonas aeruginosa. Its activity was next only to that of imipenem, meropenem and ceftazidime. CPER/SU was highly active against Acinetobacter spp., Alcaligenes spp., Burkholderia spp., Stenotrophomonas maltophilia and Flavobacterium spp., while the majority of strains of the latter two species were resistant to imipenem and meropenem. Of 3905 isolates tested, 39.5% were susceptible to CPER, 70.4% to CPER/SU. The resistance rate was 37% for CPER and 10.8% for CPER/SU.