A 60-year-old man presented with drug-resistant hypertension with hypokalemia, a high plasma aldosterone concentration (PAC) and suppressed plasma rennin activity (PRA). Imaging examinations showed multiple macronodules in the left adrenal gland. Endocrinological findings demonstrated autonomous aldosterone secretion and (131)I-adosterol scintigraphy demonstrated a left sided uptake. Laparoscopic left adrenalectomy normalized serum potassium levels and PAC, and substantially improved hypertension. Pathological and immunohistochemical analysis demonstrated that these nodules were positive for 3β-hydroxysteroid dehydrogenase (HSD3B) but not for CYP17. In addition, zona glomerulosa demonstrated "paradoxical hyperplasia", in which these cells were negative for HSD3B. All of these data indicated that the nodules in the left adrenal gland were mainly responsible for the autonomous aldosterone secretion. We conclude that the primary aldosteronism in this case was caused by multiple macronodules. This is a very rare case of primary aldosteronism caused by multiple adrenocortical macronodules.