Until recently, primary aldosteronism was considered to be a rare cause of identifiable or secondary hypertension. Over the past 10 years, a steadily growing number of reports have claimed that this condition is much more common, present in 5-40% of all hypertensive patients, which translates into many millions of patients. The primary basis for this current epidemic is the application of a relatively simple screening test, the plasma aldosterone to renin ratio (ARR). Despite growing recognition that the ARR is neither sensitive nor specific, its advocates recommend that it should be a routine procedure in evaluation of all hypertensives. Evidence is provided that this recommendation will lead to massive increases in costs, both in money and in morbidity, while providing benefit to only a very small number of patients who would not be aided by continuation of previous diagnostic protocols.