Aims An umbilical artery aneurysm is a rare vascular anomaly, associated with significant fetal morbidity and mortality. We report a case seen in our institution and review the literature on this entity. Methods A 30-year-old lady, with a background of factor V Leiden deficiency, delivered a live healthy baby at 39 weeks gestation. There were no peripartum complications. Macroscopic examination of the placenta showed a large, blood-filled cyst arising from the umbilical cord, located near the disc insertion. The umbilical cord was thin, mildly overcoiled, and had a furcate insertion. Results Microscopically, the cyst was a markedly enlarged blood vessel lined by endothelium, with smooth muscle in the wall. Subchorionic fibrin was present at the cord insertion site. No infarction, villitis or fetal thrombotic vasculopathy was identified. Conclusions Umbilical artery aneurysms are rare and associated with fetal morbidity and mortality. In this case, there were no significant fetal complications. The furcate nature of insertion of the umbilical cord may have been a contributory factor in the development of the aneurysm.