The role of cross-sectional echocardiography is demonstrated in defining the anatomy of the coronary arteries in 29 patients with complete transposition (concordant atrioventricular and discordant ventriculoarterial connections). The study revealed a relationship between some of the less frequent patterns and the spatial relationship of the arterial trunks, along with the presence or absence of a ventricular septal defect. It suggests that a side-by-side relationship of the arterial trunks due to infundibular maldevelopment may be related to some of the less common patterns.