Background. A 57-year-old woman was referred to a nephrology clinic because of chronic hypokalemia. She had a history of polycystic kidney disease, resistant hypertension, atrial fibrillation, type 2 diabetes, stroke, and end-stage renal disease, and had received a kidney transplant from a deceased donor at the age of 48 years. At presentation, the patient described symptoms of chronic fatigue and muscle aches, but she did not report pareses. Her medications included four antihypertensive agents, glucose-lowering drugs, immunosuppressants, digoxin, a coumarin derivative, and potassium chloride. Investigations. Full history, physical examination, laboratory testing of blood and urine, including aldosterone-to-renin ratio, and a saline infusion test. Diagnosis. Primary aldosteronism. Management. Treatment with spironolactone resulted in prompt control of hypertension and hypokalemia, allowing discontinuation of potassium chloride and reduction in antihypertensive medication.