11 beta-Hydroxysteroid dehydrogenase type 1 (E.C. 1.1.1.146) (11 beta-HSD 1) is a key enzyme in the metabolism of glucocorticoids, catalysing their interconversion with physiologically inert 11-keto metabolites. To identify transcription factors which may be involved in the regulation of expression of mouse 11 beta-HSD 1 we have isolated and sequenced the 5' flanking DNA to 900 bp upstream from the major transcription start site.