Mutations in the gene encoding hexokinase II which catalyzes a key step in glycolysis could contribute to the development of peripheral insulin resistance and lead to non-insulin-dependent diabetes mellitus. As a first step towards screening patients for mutations in this gene, we have determined its structure and the sequence of exon-intron junctions. The human HKII gene is composed of 18 exons that span at least 40 kb, and its organization is highly homologous to that of the rat gene. A hexokinase II processed pseudogene was discovered while screening a human genomic library. The coding sequence of this pseudogene is uninterrupted by introns and contains at least one premature stop codon.