Articles on antiplatelet "resistance" or "nonresponder" subjects now appear in the medical literature or in the media on a regular basis. The clinical consequences of such biological resistances are yet uncertain. In this review, we describe the concepts of specific and non specific resistances according to the tests used and summarize the main studies up to now. If antiplatelet drug resistances are shown to be predictive of cardiovascular events in large prospective studies, tailoring antiplatelet drugs could be beneficial and, therefore, warranted. New compounds with a more potent effect are emerging and might be useful in clinically relevant resistances.