Primary aldosteronism is a syndrome that is characterized with hypertension, hypopotasemia, high level of plasma aldosterone, and low plasma renin activity. The case we present is a 56-year-old male who referred to our neurology clinic with proximal muscle weakness and fatigue. Because of uncontrolled blood pressure, a cardiology consultation was performed for the planning of antihypertensive treatment. As prolonged QT intervals and giant U waves due to serious hypokalemia (K+:1,04), cardiology clinic took over the patient for risks of arrhythmia. After primary hyperaldosteronism diagnosis was established, the treatment was initiated and severe polyuria developed during the treatment (19L/day).