This chapter discusses ductal plate malformation. Ductal plate malformations are a heterogenous group of congenital fibrocystic liver diseases resulting from insult to the ductal plate at various stages of embryogenesis. This term was first coined by Jorgensen in 1977 for congenital liver disease involving intrahepatic bile duct system. Histology of ductal plate malformation, immunohistochemistry, development of bile duct in portal tract, and DPM-related cystic disease of liver are covered in this chapter. DPM-related cystic diseases of liver are congenital hepatic fibrosis, Caroli’s disease, autosomal recessive polycystic kidney disease, autosomal dominant polycystic kidney disease, and polycystic liver disease.