PCR walking on genomic DNA of Leptospira borgpetersenii serovar hardjobovis has identified a genetic locus comprising two heat shock genes (hslV and hslU). This is the first molecular study on hslV and hslU in a Leptospira species. The hslV gene has an open reading frame (ORF) of 543 bp coding for a 180-amino acid polypeptide (19.476 kD) with 49-62% identity to other bacterial HslV homologs. Forty-three nucleotides downstream from the hslV stop codon was found a second heat shock gene hslU with an ORF of 1401 bp encoding a 53.139-kD polypeptide of 467 amino acids with 49-56% identity to the HslU homologs from other bacteria. An Escherichia coli-like ribosome binding site (RBS) and a sigma (32)-like heat shock promoter sequence were present upstream of both heat shock genes. Identification of the hslV and hslU genes in a Leptospira species and the high degree of similarity of the encoded proteins to the E. coli homologs suggest that the encoded HslV and HslU proteins function as forming an ATP-dependent protease complex as in E. coli.