Subclavian steal may occur in newborns with interrupted aortic arch (type B) as a result of collateral circulation. Color Doppler flow imaging could detect reversed blood flow images in the diastolic phase at the subclavian artery of two neonates with interrupted aortic arch (type B), indicating subclavian steal phenomenon at the left subclavian artery via the left vertebral artery. The diagnoses were confirmed by retrograde angiography from the radial artery.