Hyperkalemia is a common electrolyte abnormality with characteristic electrocardiogram changes. Both angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) increase the risk of developing hyperkalemia. This case highlights a rare life-threatening episode of hyperkalemia in an individual whose only risk factor was an ARB. A 58-year-old female presented with sudden-onset chest pressure, light-headedness, and diaphoresis. Her initial electrocardiogram showed a nearly sinusoidal rhythm with a widened ventricular depolarization (QRS) and prolonged QT-interval (QTc). Life-threatening hyperkalemia of 9.1 mmol/L was confirmed with a rapid point-of-care electrolyte panel. She was rapidly treated with calcium, potassium-shifting and eliminating medications, and emergent hemodialysis. After stabilization, a thorough workup found that the patient’s only risk factor for hyperkalemia was her use of an ARB. While both ARBs and ACEIs are commonly associated with mild hyperkalemia, life-threatening hyperkalemia is rare, particularly in patients without concomitant renal failure, diabetes mellitus, adrenal disease, or potassium-sparing diuretic use. However, this case illustrates that life-threatening hyperkalemia is possible in patients solely taking an ARB without prior significant risk factors. Despite normal renal function in an individual without heart failure or diabetes, this patient developed life-threatening hyperkalemia.