BAG3 protein, a member of the BAG co‐chaperones family, sustains cell survival, through its interaction with the heat shock protein (HSP) 70, in a variety of normal and neoplastic cell types. bag3 gene expression is induced by stressful stimuli. Here we report for the first time that two of the three putative heat shock‐responsive elements (HSEs) in bag3 promoter interact with the heat shock factor (HSF) 1 in vitro and in vivo. Furthermore, downmodulation of HSF1 protein levels by specific small interfering (si) RNAs results in reducing BAG3 protein levels, indicating that the transcription factor plays a major role in bag3 gene expression. Because of the anti‐apoptotic role of BAG3 protein, these results disclose a previously unrecognized pathway, through which HSF1 maintains cell survival. J. Cell. Physiol. 215: 575–577, 2008. © 2008 Wiley‐Liss, Inc.