BACKGROUND AND OBJECTIVES: Combination of ticlopidine and aspirin has been accepted as a standard antiplatelet regimen after coronary stenting because it reduced the rate of cardiac events and hemorrhagic-vascular compli-cations compared with intensive anticoagulation. Ticlopidine use, however, may accompany serious side effects such as neutropenia or liver dysfunction. Cilostazol, a c-AMP phosphodiesterase inhibitor, is a novel antiplatelet agent which is known to have less side effects. MATERIALS AND METHODS: We compared the efficacy and safety of ci lostazol plus aspirin (CA) with ticlopidine plus asprin (TA) after elective coronary stenting. Patients were randomly assigned to receive either CA or TA two days before stenting. The primary end point was a composite of angiographic stent thrombosis, death, myocardial infarction (Q or Non-Q), repeat intervention or bypass su rgery at 30 days. The secondary end points were hemorrhagic-vascular complications, or drug side effects such as neutropenia, thrombocytopenia, or any side effects requiring cessation of drugs at 30 days. RESULTS: After randomization of 300 patients equally to each group, 4 patients were excluded from the analysis: 1 failure of stenting, 3 follow-up loss. The primary end point was reached in 2 patients (1.4% ) in CA group and 3 patients (2.0% ) in TA group (p=1.0). The rate of hemorrhagic-vascular complications was not different between the gr oups (1.4% vs 2.0%, p=1.0). The incidence of significant drug-related side effects was not statistically different between CA group and TA group (0.7% vs 2.7%, p=0.37). However, serious side effect such as neutropenia was seen only in TA group. CONCLUSION: Compared with TA, CA has comparable effect for the prevention of stent thrombosis and major cardiac events with similar rate of hemorrhagic-complications and drug-related side effects after elective coronary-artery stenting. Thus CA regimen can be a safe alternative to TA in elective implantation of coronary artery stent.