BAG-1 family of proteins consists of at least three polypeptides BAG-1L, BAG-1M/RAP46 and BAG-1 translated from the same mRNA. These proteins are characterized by a conserved carboxyterminal sequence through which they bind to and inhibit the action of the molecular chaperone Hsp70/Hsc70. Initially identified by their ability to bind to the anti-apoptotic protein bcl- 2, BAG-1 proteins have now been shown to interact with several cellular factors including the Raf-1 oncoprotein and a number of steroid receptors. Several functions have been ascribed to these proteins ranging from the inhibition of programmed cell death to the modulation of steroid hormone action. Recent findings on the action of the BAG-1 proteins show that although they all inhibit apoptosis, their effect on the action of nuclear receptors vary from inhibition to enhancement of the transactivation functions of the receptors. In certain cases, they even do not have any effect on the action of some nuclear receptors. Available data on negative regulation of nuclear receptor action by the BAG-1 proteins identify the nucleus as the principal site of action of these proteins. There they repress the DNA binding activity of the receptors. The process by which the BAG-1 proteins positively regulate the transactivation function of nuclear receptors is at present unknown. This review puts together recent findings on the mode of action of the BAG-1 proteins and presents them as molecular links between antiapoptotic and nuclear receptor signalling pathways.