Background: The coronary stent fracture (SF) in sirolimus-eluting stents (SES) has been known to be related with in-stent restenosis (ISR) and aneurismal change. However, the clinical effect of the SF has not been clearly evaluated yet. We sought to investigate the association of the SF and clinical outcome. Methods: From 2003 to 2008, Total 1187 lesions in 950 patients who undergoing 9-month follow-up coronary angiography were retrospectively analyzed. We reviewed the patient���s demographic and procedural characteristics that might affect the ISR after SF developed. Moreover, the major adverse cardiac events (MACE) including cardiac death, non-fatal myocardial infarction, target vessel revascularization (TVR) and target lesion revascularization (TLR) were evaluated. Results: The SF developed in 41 lesions of 39 patients (3.45%). Of 41 lesions, 17 ISR lesions (41.5%) and 5 aneurysmal changed lesions (12.2%) were observed. In the patients with SF, comparing between ISR (+) and ISR (-) group for 40 짹 17.4 months (quartile range 25.0-55.0), the incidence of MACE were significantly higher in the ISR (+) group mainly due to TVR or TLR [7 (43.8%) vs. 1 (5.0%), p = 0.012]. No event of death or MI was found in this study. The incidence of ISR was significantly higher in patients with complete typed SF compared to partial typed SF (OR 4.5, CI: 1.1-19.0, p = 0.049) and the diagnosis of acute coronary syndrome at the time of SES implantation (OR: 3.7, CI: 1.0-13.6, p = 0.047). Conclusions: The ISR related to SF after SES implantation might be associated with the adverse clinical outcome and these are more prevalent in patients with acute coronary syndrome and complete typed SF.