The outstanding feature of this publication is an updated overview on the main techniques and potential applications of fetal cardiology. This special topic issue on 'Fetal Cardiology' is a collection of review and original articles discussing novel techniques to study the fetal heart, patterns of fetal cardiac remodeling, transition to neonatal life and the potential of machine learning techniques to improve image acquisition, quantification and diagnosis. It also provides nomograms of fetal cardiac dimensions and function, and describes fetal cardiac changes associated with congenital heart disease and other fetal conditions. Therefore, this special topic issue on 'Fetal Cardiology' provides valuable reading for clinicians and researchers in fetal medicine and cardiology who are interested in the fetal heart.