Abstract: The tegumentary ultrastructure of Cyathocotyle orientalis has been described.Scanning electron microscopy shows clustered spines,ciliated papilla and non-ciliated pit-like papilla on the tegumental surface.The tegument of the holdfast is elevated into microvilli.In the transmission electron the tegument consists of a surface syncytium connected by protoplasmic strands to the cell bodies which lay below the peripheral musulature.Two types (T-1,T-2) of secretory bodies are presented in the syncytium and synthesized in the same tegumental cells.The mitochondria cells are found among the tegumental cells.The holdfast surface consists of an outer membrane elevated into microvilli and inner,fibrous basement membrane perforated by the apertures of the common ducts from the secretory cells.TEM also reveals that nonciliated pit-like papilla is glandular papilla.The tegumental ultrastructure of adult cultivated in vitro has an abnormal appearance and contains areas of vacuolation.The function of some important structures and usefulness of ultrastructural techniques to assess cultivation methods has been discussed.