SummarySeven cases of the anomalous inferior vena cava diagnosed during cardiac catheterization are described. Right heart catheterization through the saphenous vein routinely and the importance of detecting this condition before surgery is discussed. When this anomaly is diagnosed at catheterization via the saphenous vein care should be taken not to catheterize the main pulmonary artery, specially the right branch. Two simple findings on the chest X‐ray which gives a strong indication to the presence of this anomaly is mentione