Background: An aneurysm is enlargement of artery more than 1.5 times its normal diameter. Thoracic aortic aneurysms involving isthmus are very rare. Most of these aneurysms are asymptomatic and slow growing. Aortic dissection and rupture are known complications causing sudden death. Case Report: In this short communication, we present a case of 45 year old female who presented with repeated episodes of palpitations and on investigations thoracic aortic aneurysm was found. Conclusion: Homogenous opacity in the region of aortic arch can be due to aortic aneurysm. CT angiography is done to confirm the diagnosis. Endovascular repair of aneurysm is the treatment of choice with good results.