Primary hyperaldosteronism, also known as Conn’s syndrome, is the most common adrenocortical disease in cats. As in humans, this disease is underdiagnosed in cats. Cats presenting with systemic arterial hypertension, hypokalemia, or both quite often are only treated symptomatically without further investigations. This practice may potentially exclude a significant number of cats from receiving appropriate treatment. It is therefore important for general practitioners to be aware of the disease. This article describes the (patho)physiology, clinical presentation, diagnostic approach, and treatment options of for feline primary hyperaldosteronism.