Toluene-degrading bacteria were isolated from the trickle bed air biofilter (TBAB), which had eliminated toluene efficiently for three months. Among the isolates, Acinetobacter genospecies Tol 5 demonstrated the highest efficiency in toluene removal. A. genospecies Tot 5 tended to adhere to hydrophobic materials showing water-repellent. When the bacterium was grown on toluene in the presence of polyurethane foam, almost all the cells adhered to the polymer support until the amount of 0.12 kg-cell/kg-polyurethane. Analyses of cell surface hydrophobicity by the microbial-adhesion-to-hydrocarbons test and contact angle measurements revealed that A. genospecies Tol 5 has a noteworthily hydrophobic cell surface compared with Escherichia coli. A TBAB inoculated with A. genospecies Tol 5 showed a sufficiently high ability in toluene elimination within 24 h after starting the operation without preliminary operation for immobilization, suggesting that this strain was effective to shorten the adaptation period, which had been considerably long on the TBAB inoculated with the original activated sludge.