Major congenital heart disease is a very serious condition and only 15% of children survived infancy prior to the surgical era. Now over 85% of children survive into adulthood and, for the first time, there are now more adults alive with congenital heart disease than there are children. Caring for these patients has led to the development of ‘adult congenital heart disease’ as an emerging specialist area. Surgery has become increasingly specialized and technically demanding with a trend to repair lesions at an earlier age and to aim for complete anatomical repair in infancy rather than a series of staged procedures. Over two-thirds of all procedures are now carried out before the age of 1 year.