An iliac artery stent graft has a substantially inverted Y shape comprising a second arm terminating in a second end, and first and third arms terminating respectively in a first end and a third end. Each of the arms comprising a tubular graft of biocompatible graft material and the three arms joined being at a junction to allow fluid flow from the second arm into the first and third arms. In use the first end is deployed within the common iliac artery extending towards the external iliac artery, the second end is deployed within the common iliac artery extending towards the iliac bifurcation and the third end is within the common iliac artery and extends towards the internal iliac artery. Each of the three arms are mutually at an angle of approximately 120 degrees to each other. In use the first and second legs form a U shape to allow a deployment device to be smoothly deployed.