Omphalopagus conjoined twins were evaluated for elective separation. Magnetic Resonance Imaging, used for the first time in this anomaly, demonstrated a distinct, relatively avascular plane crossing a fused liver. This information permitted a nearly bloodless separation at 3-1/2 months of age. Normal growth had provided tissue for primary abdominal closure. Both twins are developing normally at 1-1/2 years of age. Timing of separation requires balancing the functional and psychological advantages of early separation against the physiological advantages of delayed separation.