SummaryA typical case of primary aldosteronism is presented. It comprises however some particular features : exchangeable potassium was not very low and remained unaltered after the removal of a large adenoma of the left adrenal. Clinical signs of diabetes became paradoxically worse after surgery.Recent methods of diagnosis of primary aldosteronism are discussed. The question of its frequency is considered : recent literature seems to indicate that this condition, despite of Conn’s hypothesis, remains an unfrequent cause of hypertension.