This chapter provides detail description of sonography of abdomen: Gall bladder and common bile duct. Chapter has 45 well illustrated diagrams and pictures. Technique of ultrasound for gall bladder, biliary sludge, cholelithiasis, acute calculus cholecystitis, acute acalculus cholecystitis, gall bladder tumors, neonatal hepatitis, biliary atresia, choledochal cyst and biliary ascaris seen on ultrasound of gall bladder and common bile duct are described in detail with the help of excellent ultrasonographic illustrations and pictures. 24 references are given at the end of the chapter for further reading