Renal artery aneurysms are uncommon vascular entities. Most are asymptomatic and are often diagnosed incidentally. Small aneurysms less than 2 centimeters are managed conservatively while those more than 2 centimeters, where the risk of rupture is increased, are surgically managed. This is a case of a 42 year old female who presented with an on and off left flank pain tor 6 months. Initial impression was renal cyst. Later on, the patient underwent renal artery angiogram at the Philippine Heart Center where a large, unruptured right renal artery aneurysm, measuring 8 centimeters in widest diameter with incidental note of ipsilateral hydronephrosis, was diagnosed. Coil embolization was done and resulted in thrombosis and total occlusion of the aneurysm while preserving the renal parenchymal perfusion. A literature review was done regarding cases of unruptured renal artery aneurysms of more than 2 centimeters diameter treated by endovascular therapy.