Heat Shock Proteins are so named stress proteins or stress molecules due to their secretion triggered by stress encountered by living beings. Although their primary documented role has been maintaining and regulating protein conformations to reduce effects of aberrant conditions faced by the host, heat shock proteins have been found to have therapeutic effects in treatments of many diseases and conditions. Those derived from certain bacteria, in particular, have been found to have high immunomodulatory potential and are being considered as adjuvants and immunostimulators in immunocompromised individuals. Extensive research has been done establishing their role as potential vaccine antigens or epitopes targeted in cancer therapies. Certain neuropathies and assumed incurable auto immune diseases have also seen light in terms of therapeusis mediated by heat shock proteins. This review focuses on giving an extensive study about multiple moonlighting roles of heat shock proteins derived from microorganisms, at molecular level, which are being used to immunize and treat diseases in many mammalian species, including humans.