A bacterial strain $5YN5-8^T$ was isolated from peat layer on Yongneup in Korea. Cells of strain $5YN5-8^T$ were strictly aerobic, Gram-negative, coccobacilli, non-spore forming, and non-motile. The isolate exhibited optimal growth at $28^{circ}C$, pH 7.0, and 0-1% NaCl. Results of 16S rRNA gene sequence analyses indicated a close relationship of this isolate to Acinetobacter calcoaceticus (97.8% similarity for strain DSM $30006^T$). It also exhibited 94.4-97.8% 16S rRNA gene sequence similarities to the validly published Acinetobacter species. The value for DNA-DNA hybridization between strain $5YN5-8^T$ and other members of the genus Acinetobacter ranged from 16 to 28%. Predominant cellular fatty acids were $C_{18:1}$ ${omega}9c$, summed feature 4 containing $C_{15:0}$ iso 2-OH and/or $C_{16:1}$ ${omega}7c$, and $C_{16:0}$. The DNA G+C content was 43.9 mol%. Phylogenetic, phenotypic, and chemotaxonomic data accumulated in this study revealed that the isolate could be classified in a novel species of the genus Acinetobacter. The name Acinetobacter brisouii sp. nov. is proposed for the novel species, with $5YN5-8^T$ (=KACC $11602^T$ =DSM $18516^T$) as the type strain.