Objective: Drug-resistant arterial hypertension can derive from unrecognized forms of secondary hypertension of which primary aldosteronism (PA) is one of the most common. While available data suggest a high prevalence of PA in patients with resistant hypertension (RH), its rate in such population is unclear. This study sought to establish the rate of RH in patients with PA and the blood pressure outcome and resistance to treatment after adrenalectomy PA-RH patients subtyped by adrenal vein sampling (AVS). Design and method: Data from consecutive patients with unambiguous diagnosis of PA and seeking surgical cure, submitted to AVS in 19 tertiary referral centers located in Asia, Australia, Europe, and North America, were collected in an observational prospective registry from 2000 to 2015. Blood pressure outcome and resistance to treatment by the American Heart Association 2018 criteria or a local clinical definition were the main study outcomes. Inclusion criteria were age > 18 years, indication to perform AVS following current guidelines, center's agreement to participate and approval of the local Ethics Committee. Results: Of 1625 enrolled PA patients, 73.7% had conclusive information on presence or absence of resistant hypertension. Of these, 20.1% were judged to have RH, a rate that raised to 49.5% according to the clinical definition of each center lead investigator. RH was about twice as common in men as in women (p < 1x10-4). Fifty-three percent of the PA patients with RH underwent surgery, which resolved resistance to drug treatment in all. Conclusions: RH is a common presentation of PA in consecutive patients seeking surgical cure; AVS-guided adrenalectomy allowed to resolve resistance of high blood pressure to treatment. Hence, the optimal management of patients with PA and RH requires subtyping with adrenal vein sampling.