Selective inhibition of COX-2 preferentially inhibits the production of prostaglandins responsible for vasodilation and inhibition of platelet aggregation. This potentially creates a pro-thrombotic state. This review examines the evidence that selective COX-2 inhibitors have adverse effects on the heart and circulation. The risk of myocardial infarction and other vascular ischaemic events, the effects on blood pressure and decompensation of treated heart failure are discussed. Conclusions are drawn about the relative risk with the different members of the drug class, and recommendations for clinical practice presented.