The use of ticlopidine in association with aspirin has reduced the incidence of subacute stent thrombosis to currently < 1% after coronary stent implantation. Clopidogrel, a more recently marketed thienopyridine derivative, has a lower incidence of side effects than ticlopidine. The use of clopidogrel in association with aspirin as compared to aspirin alone from the second through the sixth month after coronary angioplasty has been shown to reduce the 6-month incidence of major adverse cardiac events by 20-30%. Comparative studies about the use of ticlopidine and clopidogrel in patients undergoing stent implantation are scarce: these data are briefly reviewed. The conclusion is reached that, except for patients with non-ST-elevation acute coronary syndromes, there is at present no evidence that ticlopidine should be replaced with clopidogrel in all patients undergoing stent implantation; clopidogrel might be reserved for those patients who have shown side effects due to ticlopidine.