Adult congenital heart disease (ACHD) has become increasingly important in adult cardiology. A 54-year-old female presented with symptoms and signs of new onset heart failure. Echocardiography showed congenitally corrected transposition of the great arteries (CCTGA) with systolic dysfunction of the systemic right ventricle, ejection fraction was 15 to 20% and no other associated abnormalities. CCTGA is often missed in cardiology practice due to failure to recognize the abnormal position of the ventricles and the associated AV valves. One percent of patients with CCTGA are uncomplicated without VSD, PS or Ebstein's anomaly of the systemic AV valve; this was the case for our patient. Most patients present in early adulthood. The mechanism of systemic ventricular failure has been related to fibrosis due to oxygen supply and demand mismatch.