Primary aldosteronism is rare in children. We present a case report concerning an 11-year-old girl. She was referred for dizziness, fatigue, muscular weakness, and headaches. The initial evaluation showed hypertension and hypokalemia. Further tests were performed and were compatible with primary aldosteronism. Abdominal CT scanning showed an enlargement of the right adrenal gland. Histology of the removed gland revealed nodular hyperplasia, compatible with unilateral adrenal hyperplasia. Primary aldosteronism is a rare but curable cause of hypertension in children. It should be considered in all patients with hypertension.