Common arterial trunk is a rare congenital anomaly, usually found in the setting of a concordant atrioventricular connexion. The association of a common arterial trunk with absence of the right atrioventricular connexion is very rare, having, as far as we know, been reported only twice in the literature. In the case reported here the pulmonary arteries originated separately from the posterior wall of the arterial trunk, and the trunk overrode the septum between the dominant left- and the right-sided rudimentary right ventricle. We discuss the electrocardiographic features which can help in the diagnosis of this malformation.