HSP70B is a unique member of the human Hsp70 chaperone involved in cellular processes such as protein trafficking, folding, and prevention of aggregation. This protein is strictly stress-inducible, having little or no basal expression levels in most cells. HSP70B and Hsp72 are closely related and play cooperative roles in cell survival of proteotoxic stress. Recombinant human HSP70B, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography.