An endovascular delivery device (2) for a stent graft which has a pusher catheter (4), a flexible sheath (10) over the pusher catheter and at least one auxiliary catheter (32) extending between the pusher catheter and the flexible sheath. The pusher catheter has one or more longitudinal grooves (30) on its outside surface and the auxiliary catheter or catheters extend along the longitudinal grooves. A guide wire in the auxiliary catheter can be used to pre-catheterize a fenestration in the stent graft and a branch stent or stent graft delivered through the auxiliary catheter.