One hundred and eight Acinetobacter baumannii strains isolated from three university hospitals in Korea were investigated for the presence of integrons and its correlation with multiple antibiotic resistance. A. baumannii strains were classified into 23 different groups based on the biochemical tests, RAPD patterns, and antibiotic susceptibility. Many strains isolated from same hospital showed identical epidemiological markers: 75% of isolates from Gwangju, 53% from Seoul, and 39% from Cheonan appeared identical. Integrase genes were detected in 79 (73%) A. baumannii isolates. The intI1 and intI2 genes were detected in 73 (68%) and 10 (9%) isolates, respectively. Class 3 integrons were not detected. Integrase genes were detected in A. baumannii isolates from Gwangju and Seoul, but not in the strains from Cheonan. Based on the epidemiological grouping, most of A. baumannii strains affecting four or more patients carried integrons, while only one strain among the sporadic strains carried a class 2 integron. Integron-carrying A. baumannii strains were resistant to more antibiotics compared to the integron-negative strains. This result suggests that integron-carrying A. baumannii strains are more apt to spread nosocomially and to show multiple antibiotic resistances.