The gene encoding Saccharomyces cerevisiae fructose-1,6-bisphosphatase (FBP1) was isolated. Constructed fbp1::HIS3 null mutants were unable to grow with ethanol, and growth was restored after transformation with the cloned fbp gene. The gene codes for a protein of 347 amino acid residues with an Mr of 38131. Homology with the pig kidney cortex and the sheep liver enzyme is 47.7% and 46.6%, respectively, within a central core of 328 amino acid residues. The cloned promoter size was 318 bp and allowed only low level expression of the gene. This indicates a positive activation site (UAS) upstream of the cloned DNA fragment.