Abalone is economically important marine resources for fisheries and aquaculture industries worldwide. The climate changes cause the mass mortality of farmed abalone and have led to the economic loss of fisheries and aquaculture industries in Korea. In order to find genes which are involved in physiological response to temperature stress, we have performed sequencing of transcript-xome after thermal stimulation. The heat-shock response is elicited by exposure of cells to thermal and chemical stress and induces activation of Hsp70. Heat shock binding protein 1 (HspBP1) was originally identified as a protein that interacts with Hsp70 and inhibits its chaperone. In this study, molecular characterization and expression of HspBP1, named abHspBP1, were studied to understand the mechanism of heat shock response of the pacific abalone (Haliotis discus hannai) under thermal stresses. The full-length cDNA of abHspBP1 was of 981 bp, encoding a protein of 326 aa. Multiple alignments and phylogenetic analysis with the deduced amino acid of abHspBP1 showed homology with Mizuhopecten yessoensis HspBP1. Reverse transcript-xion PCR analysis indicated that the abHspBP1 mRNA in the hemocyte and gill was drastically increased at 30¡ÆC. The expression of Hsp70 in the hemocytes and gills was drastically increased at 30¡ÆC. Our present study for the first time reported the identification, molecular cloning, characterization and tissue expression analysis of HspBP1 in Haliotis discus hannai. The results of this study might provide new insights into the regulation of heat shock response in this species.