This chapter provides details about functional imaging of liver. Starting from the description about the different type of cells in the liver and their varied functions, the chapter goes on to describe different radionuclide tracers like Colloids, IDA derivatives, blood pool imaging agents, TC GSA, Gallium-67, Octreotide, FDG and more, for imaging of different aspects of liver function. There is an excellent description of various quantitative techniques for evaluation of liver function such as Hepatic Perfusion Index, Trapping Index, Hepatic Extraction Fraction, Excretion Half Time, Gall bladder ejection fraction, etc. which are currently provided only by radionuclide imaging. Descriptions of scan findings of colloid and hepatobiliary scintigraphy in various diseases such as cirrhosis, biliary atresia, cholecystitis etc are covered extensively. There are unique descriptive sections on imaging fibrosis of liver, apoptosis imaging, hepatic necrosis imaging, monitoring treatment of portal hypertension, p-glycoprotein expression imaging and imaging pleuro-peritoneal shunts. Radionuclide imaging of liver tumors including HCC, radionuclide treatment of liver tumors is described. The chapter also includes a section on splenic imaging. There is an atlas of liver scans at the end of the chapter and brief description of liver contrast enhanced USG for liver imaging.