Stroke is the third leading cause of death and the leading cause of disability in the developed world. Atherothrombosis is the underlying condition that results in events leading to ischemic stroke and vascular death. Antiplatelet therapy is commonly used for both acute stroke and in secondary prevention. Numerous trials and meta-analyses have left little doubt that antiplatelet therapy effectively reduces stroke risk in patients with prior stroke or transient ischemic attack. Current antiplatelet agents include acetylsalicylic acid, clopidogrel, ticlopidine and extended release dipyridamole with low doses of acetylsalicyclic acid (aspirin). The optimum doses of antiplatelet drugs depend upon several variables, such as genetic and environmental factors, so that clinical and laboratory response for dosage varies for each patient. Recently, the correlation between the laboratory-measurable effect of antiplatelet agents and the clinical effectiveness on the mortality of ischemic stroke and cardiovascular patients has been documented. Due to the side effect of bleeding with different antithrombotic drugs, their future employment will be determined in combination with low dosages of each component. Laboratory-controlled, tailored drug therapy will be needed for long-lasting secondary prevention of ischemic stroke.