ObjectiveTo investigate the resistance of clinical bacterial isolates to commonly used antimicrobial agents in a hospital during 2011-2012.MethodsAntimicrobial susceptibility testing of clinically isolated pathogens was performed by KirbyBauer method.ResultsA total of 3 946 pathogenic isolates were detected, grampositive bacteria, gramnegative bacteria, fungi and mycoplasma accounted for 43.92%, 37.91%, 15.91%, and 2.26% respectively.The top one isolate was Escherichia coli (16.32%), followed by Streptococcus pneumoniae (16.02%), Staphylococcus aureus (9.00%), and Klebsiella pneumoniae （7.40%） and so on. Methicillinresistant Staphylococcus aureus (MRSA) and methicillinresistant coagulasenegative staphylococcus (MRCNS) respectively accounted for 41.41%（147/355）of Staphylococcus aureus and 81.40%（197/242）of coagulasenegative staphylococcus；extendedspectrum βlactamaseproducing rate of Escherichia coli and Klebsiella pneumoniae was 68.17%(439/644) and 72.95%（213/292）respectively. The resistant rate of Streptococcus pneumoniae to erythromycin and clindamycin was 99.84% and 98.58% respectively； the resistance rate of MRSA to clindamycin and erythromycin was higher (>75%),the resistance rates of MRSA and MRCNS to vancomycin, teicoplanin and linezolid were all 100.00%；the resistance rate of Enterococcus faecium to vancomycin was 98.31%；the resistance rate of Acinetobacter baumannii to cefoperazone/sulbactam was low(8.70%), while to the other antimicrobial agents were all high； the resistance rate of Pseudomonas aeruginosa to imipenem, meropenem, ceftazidime,amikacin and ciprofloxacin were all low (<26%). Four carbapenemresistant ESBLproducing Klebsiella pneumoniae isolates and 15 pandrugresistant Acinetobacter baumannii were detected.ConclusionRegular monitor on drug resistance of bacteria helps to understand the changes in bacterial resistance in hospitals, and provide the basis for empirical antimicrobial use.