The cloned NADP-specific glutamate dehydrogenase (GDH) genes of Aspergillus nidulans (gdhA) and Neurospora crassa (am) have been shown to hybridize under reduced stringency conditions to genomic sequences of the yeast Schwanniomyces occidentalis. Using 5 and 3 gene-specific probes, a unique 5.1 kb BclI restriction fragment that encompasses the entire Schwanniomyces sequence has been identified. A recombinant clone bearing the unique BclI fragments has been isolated from a pool of enriched clones in the yeast/E. coli shuttle vector pWH5 by colony hybridization. The idenity of the plasmid clone was confirmed by functional complementation of the Saccharomyces cerevisiae ghd-1 mutation. The nucleotide sequence of the Schw. occidentalis GDH gene, which consists of 1380 nucleotides in a continuous reading frame of 459 amino acids, has been determined. The predicted amino acid sequence shows considerable homology with GDH proteins from other fungi and significant homology with all other available GDH sequences.