Pericardium patches are commonly used for the repair of congenital heart diseases. Aneurysmal dilation is a complication specific to the use of pericardial patches. Preparation of the pericardium with glutharaldehyde is considered to avoid this risk. In the present case report, we describe the development of a giant aneurysm of a heterologous patch used for closure of a ventricular septal defect in a child aged 14 days.