Patent foramen ovale (PFO) is a residual of normal fetal anatomy. More than half of babies will develop PFO at six months of age. PFO may cause shunts from right to left, and the possibility for shunting from venous thromboembolism into the arterial circulation. Since then, many idiopathic stroke studies have been conducted, in which PFOs are often found. PFO does not require follow-up treatment in infants and children, and venous thromboembolism should also be evaluated for idiopathic stroke in young patients to assess the trend of thromboembolism associated with PFO, which affects morbidity and mortality. The decision to treat depends on the presence, size and presence of complications.