Both the right-sided aortic arch with mirror-image branching (RAMI) and the congenital absence of the left pulmonary artery are sporadic congenital defects. Both diseases are typically diagnosed in childhood, but occasionally asymptomatic cases may be incidentally detected through imaging in adulthood. We reported a 43-year-old female patient with a RAMI and congenital absence of the left pulmonary artery who was relatively asymptomatic until adulthood.