A knowledge of anatomy is essential for efficient and skillful placement of central venous catheters in seriously ill patients. The anatomy of the femoral, brachial, axillary, subclavian, external jugular, and internal jugular veins is described, and landmarks useful in achieving successful cannulation are discussed. Infectious and thrombotic complications of long-term cannulation are reviewed. Catheterization of the umbilical vein in the newborn infant is a very useful alternative approach to central venous cannulation in this age group.