Persistent left-sided superior caval veins (SVC) are present in 0.4% of the population. In the majority of cases, the persistent left SVC drains into the right atrium via the coronary sinus, but direct connection to the left atrium is also recognized. Previous reports have described re-opening of persistent left SVCs in patients with congenital heart disease following bidirectional cavopulmonary connection or Fontan-type procedures, suggesting that the lumen of the left SVC obliterates during embryological development, rather than disappears. The case described in this report is, to our knowledge, the first description of obliteration of the left SVC in post-natal life, associated with spontaneous closure of a ventricular septal defect. Our observation lends further support to the hypothesis that venous structures obliterate but do not completely disappear in foetal life.