Risk stratification is key in optimizing care of patients undergoing percutaneous coronary intervention (PCI). Score algorithms, in particular, are useful prognostic tools to select the most appropriate strategy of treatment and help patients and their families to get a better understanding of issues relevant to treatment strategies and subsequent risks. Most scores tested in the setting of PCI focus on clinical variables. The SYNTAX score is a semiquantitative angiographic score developed to prospectively characterize the disease complexity of the coronary vasculature. This scoring system has recently been assessed in numerous cohorts of patients undergoing coronary revascularization by PCI or bypass surgery. When using the SYNTAX score, however, physicians are still challenged with a labor-intensive calculation and conflicting results from validation studies. Understanding how the SYNTAX score works, for which patients it works best, and whether it predicts accurately enough for its purpose is of paramount importance to get the maximum benefit from its application. The present article provides an overview of the background and the currently available evidences on the use of the SYNTAX score in patients undergoing coronary revascularization along with its limitations.