Importance: In addition to biochemical cure, clinical benefits after surgery for primary aldosteronism depend on the magnitude of decrease in blood pressure (BP) and use of antihypertensive medications with a subsequent decreased risk of cardiovascular and/or cerebrovascular morbidity and drug-induced adverse effects. Objective: To evaluate the change in BP and use of antihypertensive medications within an international cohort of patients who recently underwent surgery for primary aldosteronism. Design, Setting, and Participants: A cohort study was conducted across 16 referral medical centers in Europe, the United States, Canada, and Australia. Patients who underwent unilateral adrenalectomy for primary aldosteronism between January 2010 and December 2016 were included. Data analysis was performed from August 2017 to June 2018. Unilateral disease was confirmed using computed tomography, magnetic resonance imaging, and/or adrenal venous sampling. Patients with missing or incomplete preoperative or follow-up data regarding BP or corresponding number of antihypertensive medications were excluded. Main Outcomes and Measures: Clinical success was defined based on postoperative BP and number of antihypertensive medications. Cure was defined as normotension without antihypertensive medications, and clear improvement as normotension with lower or equal use of antihypertensive medications. In patients with preoperative normotensivity, improvement was defined as postoperative normotension with lower antihypertensive use. All other patients were stratified as no clear success because the benefits of surgery were less obvious, mainly owing to postoperative, persistent hypertension. Clinical outcomes were assessed at follow-up closest to 6 months after surgery. Results: On the basis of inclusion and exclusion criteria, a total of 435 patients (84.6%) from a cohort of 514 patients who underwent unilateral adrenalectomy were eligible. Of these patients, 186 (42.3%) were women; mean (SD) age at the time of surgery was 50.7 (11.4) years. Cure was achieved in 118 patients (27.1%), clear improvement in 135 (31.0%), and no clear success in 182 (41.8%). In the subgroup classified as no clear success, 166 patients (91.2%) had postoperative hypertension. However, within this subgroup, the mean (SD) systolic and diastolic BP decreased significantly by 9 (22) mm Hg (P <.001) and 3 (15) mm Hg (P =.04), respectively. Also, the number of antihypertensive medications used decreased from 3 (range, 0-7) to 2 (range, 0-6) (P <.001). Moreover, in 75 of 182 patients (41.2%) within this subgroup, the decrease in systolic BP was 10 mm Hg or greater. Conclusions and Relevance: In this study, for most patients, adrenalectomy was associated with a postoperative normotensive state and reduction of antihypertensive medications. Furthermore, a significant proportion of patients with postoperative, persistent hypertension may benefit from adrenalectomy given the observed clinically relevant and significant reduction of BP and antihypertensive medications..