As in any other bacterium, Helicobacter pylori synthesizes two heat shock proteins, the HspA (GroES or Hsp 10 homologue) and the HspB (GroEL or Hsp60 homologue). This article summarizes the present knowledge of genetics, function and the antigenic, immunogenic and protective properties of these two abundant proteins. H. pylori HspA and HspB antigens have vital functions for the bacterium; they share most of the bacterial chaperonin characteristics. However, the unique structure of HspA and its unique capacity to specifically bind nickel ions, strongly suggest an essential role of HspA with regard to the urease metallo-enzyme. The putative role of the H. pylori Hsp antigens in autoimmunity is also addressed.