Histomoniasis were detected and described among naturally affected of twenty three young Turkeys poult compared with the adults. Sample for study were collected from different areas of Duhok city in Kurdistan region/Iraq. Giemsa stain where used for identification of parasite from specimens of liver and cecum samples, then specimen, where fixed in 10% neutral buffered formalin for routine histopathological study. The affected birds showed clinical signs of lethargic, drooping of head and wings with progressive emaciation and a clear distinctive signs in live ones, and appearance of continuous yellowish diarrhea. Pathologically there is an enlargement and discoloration of the liver associated with appearance of white to yellow multifocal nodules in the surface of the liver. While the result of histolpathological changes showed severs inflammatory reaction around necrotic tissues with degenerative and necrotic changes of the liver cells.