Background The relation between stent fracture(SF), in stent restenosis(ISR), coronary artery aneurysm(CAA) and stent thrombosis(ST) is not well known. Method From April 2003 to March 2005, clinical data and angiographic findings of patients with stent fracture following drug eluting stent(DES) implantation who took angiography were retrospectively analyzed. Result 1. The incidence of SF is 1.0(61/6208 lesion)%, (1.6%-51/3140 in Cypher, 0.4%-8/2187 in Taxus, 0.2%- 2/881 in Endeavor) 2. SF is more common in LAD(64%) cf) RCA 33%, Cx 3% 3. Mean stent length with SF is 42.7mm (stent overlap 14%, CTO 16%) 4. The incidence of binary restenosis is 43(26/61 lesion)% (37%-19/51 in Cypher, 75%-6/8 in Taxus) 5. Improvement of LV function was noted in 8 patients out of 16 patients with prox. to mid SF and ISR(50%) 6. The MACE rate is 40(18/45 pts)% (TLR 13, CABG 1, DEATH 2, MI 2) 7. The incidence of CAA in the site of fracture is 26(16/61 lesion)% 8. The incidence of ST is 13(6/45)% (LST 1, VLST 5, All Cypher) 9. All the 6 Pts with ST & SF have aneurysms and they took dual antiplatelet agents for more than 1 year and took aspirin at the time(triple, 3 pts, dual 2 pts, single 1 pt) of ST. Summary 1. SF is highly associated with MACE. 2. SF with restenosis may be caused by continuous mechanical stress in prox. to mid LAD, along with improvement of LV function. 3. SF with Taxus showed higher rate of ISR compared to Cypher (75% vs 35%) 4. SF is closely related with aneurysms and VLST after DES implantation, especially in Cypher. Conclusion DEB(Drug eluting balloon), biodegradable stents, short stents, and CABG could be used alternative treatment for complex lesions which are prone to developing SF, considering VLST with SF was noted even with continuous dual antiplatelet therapy.