We have determined the nucleotide sequence of a stress-inducible mouse Hsp70-encoding gene named hsp70A1. The gene encodes a 641-amino-acid protein whose deduced sequence is similar to those of other members of the HSP70 family. The 5' end (tsp) of a heat-inducible mRNA is 225 bp upstream from the start codon, and several consensus recognition sequences for transcription factors lie upstream from this tsp. There are 17 putative binding sites for heat-shock transcription factor (HSF), including three clusters of multiple binding sites. We show that this upstream region is sufficient to direct heat-inducible expression of a hsp70A1::cat hybrid gene in mouse and human cells.