The most well established antithrombotic treatment for acute coronary syndromes (ACS) is unfractionated heparin (UFH) plus aspirin, but such treatment may not prevent arterial thrombotic events. Low molecular weight heparins (LMWHs) and platelet glycoprotein (GP) IIb/IIIa inhibitors offer alternative or adjunctive treatments. However, before these alternatives with higher acquisition costs are accepted in today's healthcare systems, their cost effectiveness must be proven. This paper reviews international pharmacoeconomic studies on the use of LMWHs and GP IIb/IIIa inhibitors in patients with ACS in an attempt to determine whether these therapies are cost effective. Most of the studies on LMWHs have been cost-minimisation analyses and have focused on enoxaparin sodium, because this is the only LMWH proven to be superior to UFH. Several analyses show that, compared with UFH plus aspirin, enoxaparin sodium provides cost savings both during hospitalisation (30 days) and 1-year follow-up. These cost savings are mainly attributable to fewer cardiac interventions, shorter hospital stays and lower administrative costs. Indeed, the clinical and economic advantages of enoxaparin sodium have led to its recommendation in recent guidelines as the antithrombotic agent of choice for coronary artery disease. Most of the economic analyses of GP IIb/IIIa inhibitors have been cost-effectiveness analyses. Such analyses indicate that the high acquisition costs of these drugs may be at least partially offset by reductions in other costs if a noninvasive approach to risk stratification is used. Furthermore, use of GP IIb/IIIa inhibitors appears to give favourable cost-effectiveness ratios compared with other accepted therapies, such as fibrin-specific thrombolytic therapy, in the cardiovascular field, particularly in high-risk patients and those undergoing percutaneous coronary intervention. However, more comprehensive economic data on the GP IIb/IIIa inhibitors are needed.