We present a case of a pseudoaneurysm of the superior gluteal artery following placement of an iliosacral screw in a patient with an unstable pelvic ring fracture. Percutaneous fixation of posterior pelvic ring injuries is becoming a popular method for pelvic stabilization. Several techniques are available t achieve stability and allow early mobilization in patients with displaced pelvic fractures. Percutaneous screw fixation of sacral fractures or sacroiliac joint disruptions should reduce operative and anaesthesia times as well as blood loss, while lowering the risk of surgical wound problems are decreased. The risks with this technique are generally iatrogenic, related with surgeon's lack of experience or imaging difficulties at the time of screw placement. The present case report describes an injury to the superior gluteal arterial system during percutaneous iliosacral screw insertion.