Newcastle disease (ND) is an important viral disease of poultry which is a major economic concern. It has world-wide distribution and affects a variety of avian species. The disease is characterized by marked variation in morbidity and mortality. The present study conducted to monitoring the incidence of ND in layer hen poultry houses which located in Al Zubair -Basrah governorate, during 6 month starting from September 2019 to March 2020. The study was depending on clinical examination, monitoring antibodies titer by ELISA, postmortem lesions, histopathological changes, and polymerase chain reaction (PCR). Different type of samples as proventriculus, lung, trachea, intestine, spleen, cecal tonsils ,oviduct and uterus, were collected from 6 poultry houses according to the clinically suspected diagnosis of ND. The results of the present study recorded the disease in layer hen . The positive clinical case showed significant clinical signs of ND as nervous signs and digestive signs. Sharp drop in eggs production, loss eggs pigmentations loss eggs quality. while observing the herd disappears respiratory signs. Post mortem changes recorded in reproductive ,digestive and nerves system. The sever changes on female reproductive system especially appear on ovarian follicles. Histopathological changes was in proventiculus, cecal, tonsils and spleen. The result of ELISA test during study period indicated high level during and post 7 days of infection .