The incidence of congenital heart disease (CHD) is about 4 to 10 per 1000 live births. While severe forms of CHD are usually diagnosed in infancy or childhood, milder and more survivable CHD may first manifest in the adult or may be discovered incidentally on imaging studies performed for other reasons. It is important to identify CHD in adults to implement appropriate treatment and prevent complications such as progression of pulmonary hypertension and development of heart failure. The goals of this article are to illustrate the appearance on computed tomography of various forms of uncorrected CHD in adults and describe the key features that characterize specific lesions.