The 5′ flanking region of a human dihydrodiol dehydrogenase (DDH) gene was isolated and sequenced from bp +124 to -1161. It contains putative binding sites for liver specific factors including NF-IL6 and HNF-5 sites and AP-1, AP-2 and NF kappa B-like sites. Sequence analysis identified this gene as a type II DDH. Reporter analysis of deletion constructs transfected in HepG2 cells identified negative regulatory regions and a minimal promoter (-104 to +65) containing two AP-2 sites in tandem.