The formation of an ilio-iliac arteriovenous fistula is a potentially lethal complication of common iliac artery aneurysm presentations. Whilst trauma predominantly accounts for the majority, spontaneous rupture of a common iliac artery aneurysm into an adjacent venous structure accounts for a small subset of patients. Urgent surgical intervention is warranted with the aim to restore arterial continuity and ideally, closure of the fistula. This case study describes the endovascular management of a spontaneous ilio-iliac arteriovenous fistula following rupture of a common iliac artery aneurysm into an adjacent vein.