All cells, procaryotic and eucaryotic, respond to a rise in environmental temperature by a rapid synthesis of a set of specific proteins: the heat shock proteins (HSPs). These HSPs appear to be among the most conserved proteins in nature and certain members of the HSP family are present in non-stressed cells. These observations are reflecting the fact that HSPs serve vital physiological functions as well in normal cells as in stressed cells. In the past few years, various fields of medicine have shown growing interest in the role that the HSPs may play in cellular mechanisms. In this paper we are briefly summarizing the actual knowledge of HSP involvement in carcinogenic and immunological processes.