Objective:To analyze KCNJ5 mutation of adenomas in patients with aldosterone-producing adenoma (APA) companying with hypokalemia, and to compare the clinical characteristics of patients with and without KCNJ 5 mutations.Methods:Clinical data of 144 APA patients were retrospectively analyzed. DNA were extracted from adenoma tissues, and amplified and sequenced for KCNJ5 gene. The serum potassium level and cardiac complications in patients with and without KCNJ5 gene mutation were compared.Results:Among 144 tumors, 131 tumors (91%) had KCNJ5 mutation, including 68 tumors with G151R, 56 tumors with L168R, 5 tumors with E145Q, and two tumors with novel mutations, V156_K160delITE and G151delinsVR. Compared with patients without KCNJ5 mutation, patients with KCNJ5 mutation had lower preoperative serum potassium levels, more cardiac complications, lower postoperative systolic blood pressure, and better postoperative hypertension relief. There were no statistical differences in age, gender, blood pressure, serum potassium level, plasma renin activity or plasma aldosterone concertration.Conclusion:91% adenomas in patients with APA and hypokalemia had KCNJ5 mutation, suggesting that KCNJ5 mutation is the main cause in these patients.