Diagnosis of anomalous origin of the right subclavian artery (AORSA) from the right pulmonary artery (RPA) is usually made using CT or invasive angiography. We report a patient diagnosed using transthoracic echocardiography (TTE). A newborn girl prenatally known to have d-TGA presented with cyanosis sparing the right hemithorax and arm. Oxygen saturations on the right hand were persistently higher than on the right ear and other extremities. Repeat TTE using a modified echocardiographic imaging plane allowed for full visualization of the entire subclavian artery course, revealing AORSA from RPA. We discuss further the approach to echocardiographic diagnosis and surgical implications.