We present a case of a 66-year-old woman who developed perigraft seroma after having undergone elective, open abdominal aortic aneurysm repair with a polytetrafluoroethylene graft 5 years previously. One year after graft implantation, she started to suffer from abdominal discomfort and was therefore offered surgical intervention, which she declined owing to the fear of postoperative complications. Instead, an observational strategy was used. Five years later, the patient presented with sudden severe abdominal pain. Subsequent laparotomy revealed that the pseudomembrane lining the perigraft seroma had penetrated through the native aortic wall and into the intraperitoneal cavity, where it had ruptured. The patient was successfully treated by replacing the polytetrafluoroethylene graft with a polyethylene terephthalate (Dacron) graft.