A common key question in clinical medicine is whether coronary artery disease (CAD) is present in a patient. This applies not only to patients with symptomatic chest pain, but also to those at high risk of sudden unexpected death due to asymptomatic CAD, such as diabetics. In both groups of patients, it would be of great benefit if a simple blood test could identify those most likely to have CAD. Such individuals could then be selected for more definitive but more invasive tests for CAD, such as angiography, exercise testing, etc. In addition to its established role in diagnosing heart failure, it appears that BNP may fulfil this function of pre-screening for both symptomatic and asymptomatic CAD. We review the evidence for this new prospect, which has the potential to reduce cardiac deaths by using a simple blood test to better target cardioprotective strategies to those who most need them.