Aortopulmonary window is a rare defect caused by failure of fusion of the two opposing conotruncal ridges that are responsible for separating the truncus arteriosus into the aorta and pulmonary artery. Aortopulmonary window may occur as an isolated lesion or it can be associated with other cardiac abnormalities in one third to one half of cases. The most common associated lesions are arch abnormalities, specifically interrupted aortic arch and coarctation of the aorta. Antenatal diagnosis is rare. In the current era, early mortality following repair of simple aortopulmonary window approaches zero and depends on the presence of associated lesions, especially interrupted aortic arch. Long-term outcome should be excellent. Early morbidity includes pulmonary artery stenosis and residual aortopulmonary septal defects. Long-term follow-up is indicated to look for recurrent lesions such as the development of branch pulmonary artery stenosis and arch obstruction.