Recently, the use of sirolimus-eluting stents (SES) has been demonstrated to significantly reduce the rate of adverse events among selected patients with ST-segment elevation acute myocardial infarction (STEMI). We present real-world experience from a single center registry evaluating the safety and efficacy of primary percutaneous coronary intervention (PCI) in unselected patients with STEMI using SES. Clinical outcome at 300-day follow-up in two cohorts of 225 consecutive patients who underwent bare metal stent (BMS) (January 2004-February 2005, n = 123) or SES (March 2005-December 2006, n = 102) implantation was examined. The primary endpoint was a composite of major adverse cardiovascular events (MACE: death, nonfatal reinfarction, and target vessel revascularization [TVR]). The incidence of short-term MACE was similar between the SES group and BMS group (30-day rate of MACE: 4.9% versus 8.9%, P = 0.30). Angiographically documented stent thrombosis within 30 days after primary PCI was not diagnosed in any patient in the SES group and occurred in 1 patient treated with BMS (0 versus 0.8%, P = 1.0). At 300 days, SES implantation significantly reduced the incidence of MACE (7.8% versus 22.8%, hazard ratio [HR] 0.32 [95% confidence interval (CI) 0.15 to 0.71], P = 0.005), mainly due to a marked reduction in the risk of TVR (1.0% versus 17.1%, HR 0.05 [95% CI 0.01 to 0.39], P < 0.001). There was no new onset of documented stent thrombosis between 30 and 300 days in either group. Thus, this real-world registry confirmed the safety and efficacy of SES with remarkably lower rates of TVR and MACE in the setting of primary PCI for unselected patients with STEMI in a real-world scenario.