Objective To investigate the clinical distribution and change in antimicrobial resistance of Acinetobact-er baumannii (A.baumannii)from a hospital between 2011 and 2013,so as to provide guidance for clinical treat-ment.Methods Sources and antimicrobial susceptibility testing results of A.baumannii from a hospital were ana-lyzed statistically.Results A total of 14 705 bacterial isolates were isolated in 2011 —2013,13.59%(n=1 999)of which were A.baumannii isolates,the percentage of A.baumannii in isolated pathogens in 3 years was 12.74%, 13.05%,and 14.85% respectively,which showed a rising trend (χ2 =9.458,P =0.002).The main specimen was sputum (n = 1 541 ,77.09%),bacteria were mainly isolated from patients in respiratory disease department (21 .71 %),surgical intensive care unit (16.26%),and emergency intensive care unit (8.26%).Antimicrobial re-sistance rates of A.baumannii increased year by year(all P <0.05);multidrug-resistant and extensively drug-resist-ant A.baumannii also increased year by year (all P <0.001).Conclusion Isolation rate and antimicrobial resistance rate of A.baumannii strains increase year by year,multidrug-resistant and extensively drug-resistant A.baumannii strains are obvious,which should be paid more attention in clinical department.