Before surgery for primary aldosteronism (PA), localization is evaluated with adrenal vein sampling (AVS). A 56-year-old Japanese woman had a right adrenal mass, hypokalemia, and a high aldosterone/renin ratio. Stress tests confirmed the diagnosis of PA. Subsequently, preoperative AVS was performed and right adrenal hemorrhage (AH) occurred unexpectedly. Because hypertension persisted, laparoscopic right adrenalectomy was performed. Postoperatively, the blood pressure was normalized. Pathological examination revealed an adrenal cortical adenoma largely unaffected by necrosis and hemorrhage. Previous reports have also indicated that AH may not ameliorate PA. We discussed the clinical progress of AH and the measures to prevent causing AH.