Adrenal tumors occur more frequently in women and are the leading cause of Cushing's syndrome during pregnancy. We aimed to evaluate the potential role of sex steroids in the susceptibility of women to adrenocortical tumors. We evaluated the presence of the progesterone receptor (PR), estradiol receptors (ERs), and aromatase in 5 patients with primary pigmented nodular adrenal disease (PPNAD), 15 adrenocortical adenomas (ACAs) and adjacent normal tissues, 12 adrenocortical carcinomas (ACCs), and 3 normal adrenal glands (NA). The expression of PR and ERa was evaluated by enzyme immunoassays, real-time RT-PCR, immunohistochemistry, and cytosol-based ligand-binding assays. ERb and aromatase levels were evaluated by real-time RT-PCR. ERa concentrations were low in NA, in adrenal tissues adjacent to ACA (51G33), in ACC (53G78), and lower in ACA (11G11 fmol/mg DNA). Conversely, PR concentrations were high in NA and adrenal tissues adjacent to ACA, at 307G216 fmol/mg DNA, and were even higher in tumors -726G706 fmol/mg DNA in ACA and 1154G1586 fmol/mg DNA in ACC -and in isolated PPNAD nodules. Binding study results in four tumors were compatible with binding to a steroid receptor. In patients with PPNAD, a strong positive immunohistochemical signal was associated with the sole isolated nodular regions. ERb transcript levels were very high in all samples except those for two ACCs, whereas aromatase levels were low. PR and ERb are clearly present in normal adrenal glands and adrenal tumors. Further studies may shed light on the possible pathogenic role of these receptors in adrenal proliferation.