BackgroundTetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease. It is generally diagnosed and surgically repaired early in life, with good overall outcomes.Case presentationWe report the case of a patient incidentally diagnosed with paucisymptomatic TOF at the age of 56 years old, during investigations for carbon monoxide poisoning. The patient had a history of thyroidectomy, arterial hypertension, and four uncomplicated vaginal deliveries.ConclusionsThis case shows us that some patients with TOF can reach older ages without surgical correction. Late surgical repair should be meticulously decided on a case basis.Supplementary InformationThe online version contains supplementary material available at 10.1186/s43044-023-00372-3.