Background: Chronic renal insufficiency (CRI) is one of well known risk factor in patients (pts) with coronary artery disease (CAD) and combined left main disease may lead worse prognosis. Methods: A total 180 consecutive pts with ULMCD underwent PCI with DES were enrolled for the study. Study population were divided into two groups according to renal funtion.CRI was defined as baseline serum creatinine more than 1.5 mg/dl. We evaluated the impact of CRI on angiographic and clinical outcomes up to 12 months following percutanous coronary intervention (PCI) with drug eluting stents (DES) in pts with unprotected left main coronary disease (ULMCD). Results: Baseline clinical and procedural characteristics were similar between the two groups except the lesion length was longer in CRI group. At six months angiographic follow up, CRI group had higher incidence of late loss and aneurysm formation. At twelve months, despite the other major clinical outcomes including the incidence of Q-MI, repeat PCI and major adverse cardiac events (MACE) were similar between the two groups, the CRI group had higher incidence of total death and cardiac death (Table 1). Conclusions: Regarding PCI for ULMCD with DES, CRI was associated with higher incidence of late loss and aneurysm formation at six months angiographic follow up and worse clinical outcomes, specifically higher incidence of deaths at twelve months. Special care would be warranted for CRI pts with ULMCD.