The diagnosis of vascular ring with right aortic arch allows early treatment after birth preventing morbidity in infants and older children. We describe the sonographic findings of two patients with right-sided aortic arch associated with aberrant left subclavian artery and left ductus arteriosus. Two women at 24 weeks pregnant aged 18 and 24 years old underwent a thorough echocardiographic evaluation of the fetal heart by targeted visualization of the three-vessel view at the Cardiocentro Pediatrico “William Soler” , using an ATL HDI 5000 ultrasound machine made in USA with a 3 MHz transducer. The presence of a right-sided aortic arch, left ductus arteriosus and aberrant left subclavian artery was detected in both cases. Color Doppler ultrasound demonstrated the presence of Kommerell’s diverticulum. One of the fetus also presented Tetralogy of Fallot and the woman opted for abortion. Both prenatal diagnoses were confirmed, one by postnatal echocardiography and the other by histopathological study. The presence of right-sided aortic arch, left ductus arteriosus and aberrant left subclavian artery is an uncommon anomaly that can be detected by prenatal ultrasound.