We report a rare case of haemangiopericytoma/solitary fibrous tumour of the greater omentum in a 41-year-old woman. It presented as a large mobile abdominal mass measuring 30 × 24 × 8 cm. A computed tomography scan confirmed the presence of a large vascular tumour, and biochemical tumour markers were non-contributory. The tumour was removed through a conventional laparotomy incision with the aid of a Ligasure dissector. There were no macroscopic metastases, and histologically it was benign. The size of >5 cm, however, suggests that it may have been malignant. In the absence of visible metastases and in view of the favourable histological features, it was decided to follow up the patient very closely and give further treatment if necessary.