Coronary artery aneurysms are relatively rare and commonly associated with significant coronary artery disease (CAD), inflammatory diseases (Kawasaki syndrome, infection), or iatrogenic complications. Herein, we report an unusual case of an incidental coronary aneurysm of the left main artery in a patient without specific clinical symptoms of myocardial ischemia or systemic inflammation and without angiographically significant CAD. Angiographic images are provided, acquired during cardiac catheterization, as well as coronary computed tomography angiography (CCTA) images obtained at 1 year of followup.