Aortic abnormalities are now frequently diagnosed during fetalFetal life due to the incorporation of upper mediastinal views into routine screeningScreening views of the fetal heartFetal heart. Morbidity and mortality is reduced when duct-dependent lesions such as coarctation of the aortaCoarctation of the aorta are diagnosed prenatally. Lesions such as double aortic archDouble aortic arch and right aortic archRight aortic arch have become more commonly diagnosed as a result of incorporation of the three vessel and trachea view to screening and this facilitates prenatal geneticGenetics testing and parental awareness of potential postnatal issues. All aortic archAortic arch abnormalities can be associated with intracardiacIntracardiac abnormalities so assessment of the intracardiacIntracardiac anatomy is mandatory. This chapter however focuses on isolated abnormalities of the aortic archAortic arch and its branches.