Obstructive uropathy following abdominal aortic surgery can no longer be considered a rarity. Early hydronephrosis, developing in the first postoperative year, occurs in 10% to 20% of patients; it usually runs a benign, self-limiting course. The incidence of delayed ureteral obstruction, which develops or persists after the first postoperative year, is unknown because it is asymptomatic in most cases. Although spontaneous resolution is possible, it seems that this late form is more likely to persist. The diagnosis of postoperative hydronephrosis is not an indication for urologic intervention. This should seldom be necessary; it should be reserved only for patients with evidence of worsening obstruction or deteriorating renal function. Early and particularly, delayed hydronephrosis seems to be a marker for present or impending graft complications, such as infection or false aneurysms. A prolonged follow-up is therefore mandatory whenever the diagnosis is established as it may improve long-term survival and limb salvage. The need for routine screening for this condition remains to be established. With the availability of noninvasive methods, such a task could be easily accomplished.