The nucleotide sequence of the SHV-5 beta-lactamase gene, subcloned from a plasmid of Klebsiella pneumoniae, was determined. The amino acid changes thought to be responsible for the extended substrate profile of SHV-5 are Gly----Ser234 and Glu----Lys235. SHV-5 is identical to SHV-4, except for Leu----Arg201, which accounts for the difference in apparent pI of the two enzymes.