Seventy-seven Acinetobacter isolates were recovered from patients in a Korean hospital during the period from November to December 1998. The isolates were genotyped using randomly amplified polymorphic DNA (RAPD) analysis for epidemiological relationship, and investigated for antibiotic susceptibility and presence of integrons. Sixty-nine Acinetobacter baumannii isolates were distributed into five groups by RAPD profiles, with 5, 1, 60, 2 and 1 in each group. The major RAPD group of 60 isolates was further divided into six subgroups by antibiograms. Eight isolates belonging to Acinetobacter DNA group 13TU were distributed among six RAPD groups. Seventy-three of the Acinetobacter isolates were resistant to eight or more of the antibiotics tested. Integrase genes were detected in 66 of the 69 A. baumannii (96%) and in 5 of the 8 Acinetobacter DNA group 13TU isolates (63%). The intI1 and intI2 genes were found in 63 and 8 isolates, respectively. The intI3 gene was not detected. All integron-carrying isolates were resistant to multiple antibiotics. All strains isolated from more than one patient carried integrons. According to the results, the presence of integrons was significantly (p<0.01) associated with multiple antibiotic resistance and nosocomial spread in Acinetobacter strains.