The prevalence and characteristics of patients operated for adrenal adenoma (Conn syndrome) as well as their post-operative arterial pressure evolution are varying through literature. Our aim was to report the Grenoble University Hospital experience. From 1993 to 2005, 24 patients (mean age = 46 +/-11 years) presented the biological criteria of primary hyperaldosteronism and benefited from adrenalectomy with confirmation of adrenal adenoma. All had an uncontrolled hypertension, refractory in 42% of cases, with a hypokaliemia (mean = 2.65 +/- 0.47 mmol/l). All adenomas measured more than 10 mm in scanner imaging. After a mean post-operative follow-up of 46 +/- 43 months, 70% of them were normotensive, with (45%) or without (25%) anti-hypertensive therapy. the post-operative kaliemia was normal in all cases. Only 25% had post-operative hormonal dosages for control. Post-operative spontaneous normotensive patients had, at the diagnosis of adrenal adenoma, a more recent and non-refractory hypertension, with a lower number of antihypertensive drugs, a better response to spirinolactone and higher aldosterone plasmatic levels. Two lessons can be taken from this study: 1) Whether 70% of patients operated for adrenal adenoma are normotensive (with or without treatement) post-operatively, only 25% are definitely cured after 4 years. Factors associated to a post-operative cure highlight the interest of an ealy diagnosis. 2) There is probably an underdiagnosis of adrenal adenoma (Conn syndrome) because neither adenomas with normokaliemia, nor adenomas <10 mm in scanner imaging have ever been diagnosed or at least, sent to surgery.