Cardiac magnetic resonance imagingCardiac magnetic resonance imaging (CMR) is widely used in the diagnosisDiagnosis and assessment of congenital heart diseaseCongenital heart disease (CHD) in postnatal life. Whilst technical constraints have historically limited its application in fetalFetal cardiology, recent technological advances in CMR have led to its emerging use as an adjunct in the diagnosisDiagnosis of structural fetalFetal cardiac defects. It has an additive role in diagnosing associated extracardiacExtracardiac abnormalities, such as co-existing lung pathology, lateralityLaterality disorders and brain lesions. Quantification of flowFlow and oxygen content by CMR allows assessment of changes in the fetalFetal circulation in the setting of structural heartHeart disease in the third trimester. These advances currently serve as research tools but already demonstrate potential to form part of mainstream clinical care in the coming years.