Liver, the largest gland in the body receives total perfusion of 1500ml per min even in inactive state. The introduction of Computerised Tomography has made imaging of liver more detailed and safe. The liver is divided into eight vascular segments. Each of them receives a portal pedicle. The ramifications of hepatic veins define intersegmental planes. Aims: Pattern of ramification of both portal and hepatic veins, internal diameter of these vessels and their angulation is measured. Methods and Material: CT scans of 50 adult patients both male and female for indications other than liver pathology and clinically normal liver were included in the study. Results: Portal vein divides into three branches, namely Left branch of portal vein, anterior and posterior segmental vein; branches of right portal vein in 12% of cases. Patterns of drainage of hepatic veins indicate variable internal architecture. Internal diameter of vessels and ramification within 1 cm from IVC determine surgical plan. Conclusions: Pattern of internal architecture is unique for each individual. Preoperative CT scan will help to plan resection along the intersegmental plane with minimal loss of liver tissue. The liver transplantation is done using cadaver donor or partial transplantation using live donor. In trauma and malignancy, the affected lobe and segments of liver can be resected preserving the rest, which can hypertrophy to compensate for the loss.