The gene encoding dextranase was isolated from the genomic DNA of Arthrobacter sp. AG-2 by using E. coli DH5alpha as host. DEX-probe amplified by DEXFWD2 and DEXREV primers, designed from conserved regions of 3 dextranases, was labeled with DIG and used for detection of dextranase gene by Southern and Dot blot hybridization. The 1.9 base pairs BamHI fragments was cloned into pGEM-7Zf(+) designated as pSUDEX1 and contained 5’ portion of dextranase gene as indicated by homology comparison. To isolated 3’ end of sdx, the PstI-BamHI fragment (PB-probe) obtained from 3’ end of SUDEX1 was used as probe to clone 3’ portion of gene designated as SUDEX2. SUDEX2 fragments lacked stop codon and downstream element. Similarly, BP-probe obtained from 3’ end of SUDEX2 was used as probe to clone the remaining portion of the gene (SUDEX3). The complete dextranase gene contained 1,899 base pairs and encoded a protein of 633 amino acids with expected molecular weight of 70.3 kDal. A putative ribosome binding site and inverted repeat were also found. The amino acid sequence identity compared with endodextranase from Arthrobacter globiformis T-3044, dextranase from Arthrobacter sp. CB-8 and isomalto-triodextranase from Brevibacterium fusum var. dextranlyticum were 83%, 82% and 79% respectively. The deduced amino acid sequences contained 7 conserved regions among endodextranase, isomalto-triodextranase and isopullulanase. Finally, SUDEX3 was cloned into pSUDEX1 in order to construct complete gene.