Common arterial trunk (CAT), also called truncus arteriosus, is a congenital heart defect that is characterized by a single arterial trunk arising from the heart. The arterial trunk overrides the interventricular septum and gives rise to the systemic, pulmonary, and coronary circulations. The nomenclature for CAT has undergone significant revisions owing to the recognition of varying pulmonary artery origins, interrupted aortic arch, and relative sizes of the aortic and pulmonary trunks, leading to a more generalized categorization based on aortic or pulmonary trunk dominance. This chapter will review the operative steps for repair of common arterial trunk and the complications that might arise during the conduct of the operation.