A soil bacterium was isolated from maize roots cultivated in Korea (KNUC153). The isolate was partially classified on basis of l6S rDNA sequence analysis as Stenotrophomonas maltophilia. By the acetylene reduction assay (ARA), the strain KNUC153 contained nitrogen-fixing abilities. The amount of auxin produced by the strain KNUC153 was $77.6;{mu}g/ml$. The strain KNUC153 produced 4 times higher amount of l-amino-cyclopropane-l-carboxy­lic acid deaminase than that of the other known strain Azospirillum sp. KNUC82. Inoculation treatment with the strain KNUC153 for maize seeds showed positive effect on early growth of the plants.