Primary aldosteronism (PA) is the most common cause of secondary hypertension (HT). We describe here clinical characteristics, diagnostic procedures, and long-term outcomes in a Norwegian population. All suspected PA patients investigated at a tertiary centre from 1998–2012 were retrospectively evaluated. Inclusion criteria were verified PA after confirmatory testing or otherwise considered highly likely PA. Clinical, biochemical, radiological, and adrenal vein sampling (AVS) findings were analysed. Surgically removed adrenals were re-evaluated histopathologically and tested for somatic mutations. All patients still alive by August 2014 were invited to a follow-up visit. One-hundred and eight patients were included, of whom 85% had a history of hypokalaemia. PA was verified by confirmatory testing in 83 (77%), and AVS performed in 95 (88%) patients. The proportion with AVS-confirmed bilateral PA increased during the study period. Sixty-eight patients (63%) underwent adrenalectomy. KCNJ5 mutations were found in 30% of the surgical specimens and were associated with female sex and a florid PA phenotype. Follow-up visits were undertaken in 73/108 (68%), of whom 52 adrenalectomised. After adrenalectomy, 83% were biochemically cured of PA, but only 21% were cured for HT. Female sex, a verified adenoma, and KCNJ5 mutations were associated with cure of HT. In conclusion, the majority of our patients had unilateral PA and hypokalaemia, indicating that patients with bilateral and milder PA may still be underdiagnosed. Female sex, a histopathological adenoma, and the presence of KCNJ5 mutations predicted cure of HT after adrenalectomy, but the overall cure rate of HT was low.