OBJECTIVE To survey the hospital infection of Acinetobacter baumannii in an ICU during one week's time,and study its antibiotic resistance pattern and homogeneity.METHODS The antibiotic resistance patterns of 17 A.baumannii strains were obtained by K-B method,and their homogeneity information was determined using random amplified polymorphic DNA(RAPD).RESULTS Twelve strains of A.baumannii were isolated from the ICU,among which 3 were isolated from patients,and 9 were isolated from the surface of facilities in the ICU.Eleven strains were found to be multi-antibiotic resistant,and their resistance patterns were the same with the 5 strains from patients.RAPD results showed that the 3 strains from patients and 8 strains from the environment had the same genotype.CONCLUSIONS A small outbreak of a genotype of A.baumannii infection happens in the ICU.