In the past 2 decades, endoscopic sinus surgery has been widely used as a safe and effective treatment for disorders of the paranasal sinuses that are refractory to medical therapy. Advances in surgical technique, including powered instrumentation and stereotactic image-guided surgery, have improved the efficiency and safety of this procedure. These techniques have been further expanded to manage skull base pathologies. This expansion has been facilitated by a better understanding of the endonasal skull base anatomy. Despite these advances, complications are still encountered. Vascular injuries are particularly troublesome. Interior ethmoid artery injuries during sinus surgery that led to orbital hematoma were discussed extensively in a recent issue of this journal. Therefore, this article focuses mainly on inadvertent carotid artery injuries during routine sinus surgery and vascular injuries during endoscopic skull base surgery.