A 35-day-old boy weighing 4.5 kg was referred to our department from a general paediatric hospital due to low oxygen saturation. His transcutaneous oxygen saturation was 75%. Transthoracic echocardiography showed discordant ventriculo-arterial connections, a non-restrictive atrial septal defect, and patent ductus arteriosus, in addition to a 23 mm×10-mm left atrial appendage aneurysm. As far as we know, this association has not been reported previously in the literature.