Conjoined twins are the most extreme form of twinning, occurring in about 1% of monozygotic twins with incidence of about 1 in 50,000 to 1 in 100,000 births. However 60% are still born or die shortly after, the true incidence is around 1 in 200,000 live births.1 The antenatal diagnosis is difficult clinically but extremely important. The prenatal diagnosis of conjoined twins is usually suggested at prenatal sonography, which has the advantage of offering a safe, accurate, and reliable method of detecting anomalies of foetal growth and structure.2,3 However, because of the intrinsic limitation of sonography with regard to tissue contrast, MRI has been explored as a safe alternative. We present a case of conjoined twin (Craniopagus and Thoraco-omphalopagus) diagnosed by ultrasound and MRI at 15 weeks of gestation.