Abstract Introduction To date, case reports have shown an association between paraganglioma and primary hyperaldosteronism, and primary hyperparathyroidism with primary aldosteronism, but not for all three of the aforementioned endocrinopathies combined. Clinical Case A 54-year-old woman with history of uncontrolled HTN, hypokalemia, DM2, CKD stage III, Takotsubo cardiomyopathy and primary hyperparathyroidism presented to the hospital with back pain. CT scan showed a 4.3 cm necrotic retroperitoneal mass. Due to her labile blood pressure, ranging from 194/102 mmHg to 106/60 mmHg, endocrinology was consulted for evaluation of secondary hypertension. Plasma normetanephrines were 3447 pg/mL (n ≤ 57 pg/mL), 24-hour urine normetanephrines 5954 mcg/24 hours (n 122-676 mcg/24 hours) and 24-hour urine norepinephrines 476 mcg/24 hours (n 15-100 mcg/24 hours). 24-hour urine cortisol and 24-hour urine metanephrines were within normal limits. Plasma aldosterone level and plasma renin activity (PRA) were 19 ng/dL and 0.78 ng/mL/h (n 0.25-5.82 ng/mL/h),. However, the patient was also taking spironolactone and telmisartan which interfered with results, and withdrawal of interfering medications was considered unsafe. 68Ga-DOTATATE PET/CT showed mild uptake in a left para-aortic mass. Genetic testing did not show pathogenic mutations of AP2S1, CASR, MEN1, NF1, RET, SDHA, SDHAF2, SDHB, SDHC, TMEM127 or VHL genes. The patient was started on doxazosin and underwent successful removal of the left retroperitoneal mass consistent with paraganglioma. Six months later, surveillance testing showed normalization of fractionated plasma metanephrines and of 24-hour urine metanephrines. However, due to blood pressure of 152/100 mmHg and K of 2.8 mmol/L (n 3.5-4.7 mmol/L), concern was raised for primary hyperaldosteronism. After potassium repletion, labs showed plasma aldosterone of 37 ng/dL, PRA of 0.2 ng/mL/h (n 0.25-5.82 ng/mL/h) and ARR of 185 with potassium of 4.1 mmol/L (n 3.5-4.7 mmol/L) consistent with primary hyperaldosteronism. MRI of adrenal glands showed a left adrenal gland that was thickened and nodular but without discrete nodules > 1 cm. The patient was referred for adrenal vein sampling. Five years previously, the patient had been diagnosed with primary hyperparathyroidism, with PTH of 188.5 pg/mL (n 14-64 pg/dL), Calcium of 10.6 mg/dL (n 8.5-10.1 mg/dL) and GFR of 39. Pre-operative imaging with MRI neck had shown enlargement of two parathyroid glands. She had undergone two-gland parathyroidectomy with intraoperative PTH decrease of > 50% and normalization of calcium. However two weeks later, her PTH returned to pre-operative levels (with normal 25(OH)D) and continues to remains elevated. This has been attributed to underlying secondary hyperparathyroidism from her chronic kidney disease. Conclusion To our knowledge, this is a unique case of combined paraganglioma, primary hyperaldosteronism and primary hyperparathyroidism, as thorough literature review has not shown such a coexistence in the past. Presentation: No date and time listed