Eleven strains of endophytic actinomycetes were isolated from healthy roots of Acacia auriculiformis A. Cunn . ex Benth. collected from Bangkok and Nakhonpathom, Thailand. No actinomycete could be isolated from leaf samples. Analysis of 16S rRNA sequencing of those strains revealed that they belong to members of genera Streptomyces , Actinoallomurus , Amycolatopsis , Kribbella and Microbispora . Within 11 endophytic actinomycetes, GMKU 944 showed strongest antibacterial activities against tested bacteria and fungi. In this work, the residing property of endophytic actinomycetes in the roots of wattle tree was verified by inoculation of GMKU 937 to germinated seeds. It was demonstrated that GMKU 937 could be re-isolated and was a true endophyte.