Background:There have been several reports about the predisposing factors and clinical courses of stent fracture(SF) after drug-eluting stents(DES) implantation but they were not conclusive up to date. We investigated the clinical, angiographic, stent, and the procedural variables that may predispose to SF ,and long-term clinical outcomes. Methods:From April 2003 to June 2007, cases with SFs were collected from single center. SF was defined as single or multiple stent strut fracture as well as complete separation of stent segments. Results: 37 SFs were identified in 21 patients. The proportion of vessel distribution was predominat in LAD(73.5% in LAD, 29.4% in RCA, and 3.2% in LCX). Meticulous analysis of angiography revealed that all SFs were developed in 2 lesion conditions. First was lesion that serves as hinges with or without excessive tortuosity, in which case all of the SF were developed in hinge point (16 case: 76%, 30 SFs: 81%). Second was lesion with stent overlapping in long curved lesion leading to longitudinal straightening of the vessel, in which case most of SF were developed at edge of overlapped stent (5 case; 24%, 7 SFs: 19%). Most of all fractures occurred in sirolimus-eluting stents except for 2 cases. Adverse clinical outcomes associated with SF occurred in 13 patients ( 1 death due to stent thrombosis, 3 stent thrombosis, 11 binary restenosis, 11 target lesion revascularization) during a mean 30.3짹16.7 months long-term follow-up period after index PCI( a mean 7.9짹5.7 month after detection of SF). Conclusion: Potential predisposing factors may be mechanical stress such as hinges and countervailing force to its original shape and stent conformability determined by stent structure since most of all fractures occurred in sirolimus-eluting stents. Stent fracture might be associated with the high incidence of target lesion revascularization and a new potential mechanism of stent thrombosis during long term clinical course.