Abnormalities of the pulmonary and systemic veinsSystemic veins have a wide range of severity, from inconsequential variations of normal to being part of major complex congenital heart diseaseCongenital heart disease. They can be challenging to diagnose and image, as there is a broad range of normality in the anatomy of venous structures, and they are often small structures with low velocity blood flowFlow. For some lesions, antenatal detection rates remain very low. The abnormalities that will be discussed in this chapter include left-sided superior vena cavaSuperior vena cava, agenesis of the ductus venous, interrupted inferior vena cava, and total / partial anomalous pulmonary venous connection. Disorders of lateralityLaterality are also discussed in this chapter because of their frequent association with venous variations / abnormalities which are often the first clue to the diagnosisDiagnosis.