Aldosterone synthase (AS) is encoded by the CYP11B2 gene, a candidate for familial hypertension. CYP11B2 was previously mapped to chromosome 8q but its precise localization is necessary for genetic studies of hypertension. The present study reports the genetic mapping of the human CYP11B2 gene by radiation hybrid (RH) analysis, the isolation of a bacterial artificial chromosome (BAC) containing this gene and its physical mapping by fluorescent in situ hybridization (FISH). The CYP11B2 locus is on the most distal segment of the long arm of chromosome 8, proximal to the microsatellite polymorphic marker D8S1704. This location, which was confirmed by FISH, is approximately 60cM telomeric to the currently listed human gene locus (chromosome 8q21-22) and corresponds to cytogenetic band 8q24.3. The BACs containing the gene and a high-resolution map of the CYP11B2 locus are useful for genetic studies of hypertension and other endocrine disorders.