The authors defined precaval retropancreatic space as the space between pancreatic head with portal vein and IVC analyzed the CT findings of this space to know the normal structures and size in this space, We evaluated 100 cases of normal anbdominal CT scan to find out normal anatomic structures of precaval retropancreatic space retrospectively. We also measured the distance between these structures and calculated the minimum, maximum and mean values. At the splenoportal confluence level, normal structures between portal vein and IVC were vessel (21%), lymph node (19%), and caudate lobe of liver (2%) in order of frequency. The maximum AP diameter of portocaval lymph node was 4mm. Common bile duct(CBD) was seen in 44% and the diameter was mean 3mm and maximum 11mm. CBD was located in extrapancreatic (75%) and lateral (60.6%0 to pancreatic head. At IVC-left renal vein level, the maximum distance between CBD and IVC was 5mm and the structure between posterior pancreatic surface and IVC was only fat tissue. Knowledge of these normal structures and measurement will be helpful in differentiating pancreatic mass with retropancreatic mass such as lymphadenopathy.