Shiga-like toxin (SLT), which is produced by E.coli O157:H7, the most widespread strain, is composed of enzymatically active A and B subunit multimers responsible for the toxin’s binding. In this study we have made recombinant SLT-I B coding gene by ligation of SLT-I B (leading sequence) and SLT-II B (lagging sequence), in order to maximize protein expression yeild. The recombinant SLT-II B subunit has been expressed by using T7 promoter (pRSET B) in E. coli BL21 (DE3). The obtained SLT-II B recombinant protein will be further used in antibodies and subunit vaccine development