Two hundreds of layer chickens were sampled from 100.000 layer hens of different eges that showing clinical sign and gross lesions from different farms in sharkia governorate from January to april 2008 aspergillus app. Were isolated and identified morphologically on cultural basis. Morbidity rate was reached 40% and mortalily rase more 7%. Clinical signs were mainly resptratory characterized by gasping, dyspnea and accelerated breath. The most commom griss lesions were caseased nodules distributed in lung air socs, inlestine, heart and liver, Microscopic picture revealted granulomasous lesions with or without hyphae. Those lesions represented by caseated nodules.