Summary: Hyperkalemia is a common electrolyte disorder often resulting from reduced renal potassium excretion or its shift out of cells in conditions such as rhabdomyolysis or tumor lysis syndrome. It can be diagnosed in outpatients, as well as in hospitalized patients, and may have a benign character or – in severe cases – it can be life-threatening and lead to fatal arrhythmias. Severe acute hyperkalemia is, therefore, a challenge for physicians and requires aggressive therapies. Chronic hyperkalemia is a frequent complication of guideline-directed medical therapy in patients with chronic kidney disease or heart failure, which often enables its continuation. In the article, after a short review of the causes and the clinical presentation, we focus on its treatment options both in the acute setting and in chronic hyperkalemia, where the use of new potassium removing agents, patiromer and sodium zirconium cyclosilicate, may allow for optimization of cardiac therapy.