Glucocorticoid-remediable aldosteronism (GRA), also known as familial hyperaldosteronism type I (FH-I, OMIM 103900), is a monogenic form of inherited hypertension caused by the presence of a chimaeric gene originating from an unequal cross-over between the CYP11B1 (11?-hydroxylase) and CYP11B2 (aldosterone synthase) genes. The hybrid gene has the CYP11B1 sequence at the 5' end, including the promoter, and the CYP11B2 sequence at the 3' end. The aim of our study was to evaluate the prevalence of GRA in a Polish population of 129 patients with primary hyperaldosteronism (PHA) and 132 patients with essential hypertension (EH), through the use of a PCR-based test revealing the chimaeric gene. None of our PHA or EH patients was positive for the CYP11B1/CYP11B2 chimaeric gene. These data suggest that GRA is unlikely to be a common cause of hypertension in Polish subjects. However, the real prevalence of GRA in Poland, both in the high-risk group of individuals with primary hyperaldosteronism and in the general population, remains to be established.