Abstract
This book chapter presents the classification of subfamilies under the Family Opisthorchiidae (Opisthorchiinae, Allogomtiotrematinae, Delphinicolinae, Diasiellinae, Metorchiinae, Microtrematinae, Oesophagicolinae, Pachytrematinae, Plotnikoviinae, Pseudamphistominae, Ratziinae, Tubangorchiinae, Witenbergiinae). Morphological characteristics of members of the Family Opisthorchiidae are discussed. Members of this family are known parasites of mammals and birds, fish and reptiles. A key to subfamilies and genera is included.