Thoraco-omphalopagus asymmetric conjoined twinning is a rare condition in which a grossly defective foetus (the parasite) is attached to the thorax and upper abdomen of the main foetus (the autosite). We describe a case of thoraco-omphalopagus asymmetric conjoined twins in which the autosite had an associated large-diameter omphalocoele that was successfully separated at our institution. Reconstruction of the resulting abdominal-wall defect was performed using a flap from the gluteal region and the proximal portion of the inferior limb of the parasite, which is demonstrated. In addition, a review of all previously published cases is presented, showing that overall positive results can be obtained in treating this condition and that the presence and degree of cardiac involvement have a major influence on the prognosis.67e18-21