The optimal duration of treatment with clopidogrel after percutaneous coronary intervention (PCI) with stent placement remains controversial. The Randomized Argentine Clopidogrel Stent (RACS) trial was a prospective, randomized, nonblinded study of 1,004 patients undergoing PCI who were randomized after successful bare metal stent placement to 30 versus 180 days of clopidogrel; all patients also received aspirin. Patients were eligible regardless of whether they had presented with ST-elevation myocardial infarction (MI), acute coronary syndrome, or stable angina. The primary end point was a composite of death, MI, and stroke at 180 days. Baseline clinical characteristics showed no differences between groups in terms of age, gender, history, risk factors, or incidence of diabetes; 72% presented with an acute coronary syndrome and 15% had MI as the indication for PCI. At hospital discharge and 30 days, when the 2 groups received the same treatment, there were no significant differences between groups in frequency of death, MI, or stroke. However, from 30 days to 6 months, patients assigned to 6 months of clopidogrel reached the primary end point of death, MI, and stroke less frequently (4.99% vs 1.74%, p = 0.010, relative risk decrease 65%). No significant between-group differences were found in frequency of total bleeding (0.64% vs 1.52%, p = 0.34) for the control and study groups. In conclusion, after successful placement of a bare metal stent in a coronary artery, patients treated with 6 months of clopidogrel showed a trend toward fewer adverse events compared with those treated for 30 days.