Anomalous origin of the left circumflex artery (LCA) arising from the right coronary sinus was observed in a 45 year-old man with aortic root aneurysm. Valve-sparing aortic root replacement (VSARR) was decided despite the subannular course of the LCA. A modified Tirone David procedure was performed with specific consideration for distribution of the proximal suture line due to the peri-aortic and subannular course of the LCA. Due to the risk of LCA injury, a coronary artery bypass grafting was performed using the left internal thoracic artery to secure the perfusion of the LCA. The challenging association of aortic root aneurysm and anomalous origin and course of the LCA was managed successfully during VSARR.