Chicken infectious anemia (CIA) is a worldwide, highly contagious immunosuppressive viral disease of young chickens 4-6 week of age caused by chicken anemia virus (CAV). It is implicated in several field problems of economic significance after maternal antibodies have waned. CAV threaten poultry industry alone or either coinfection with infectious bursal disease virus (IBDV) or inclusion body hepatitis (IBH). This paper aimed to understand the pathogenesis of this existing condition. Three hundred chickens from fifteen selected commercial broiler flocks (7 Cubb and 8 Native breeds) were collected from different areas of Dakahlia Governorate Egypt during the period from October 2019 to September 2020. Necropsy was carried out on freshly dead or diseased birds beside blood samples for hematological changes. Tissue samples were subjected to PCR assay for detection of CAV DNA, IBDV RNA and IBH DNA. Conventional PCR test indicated that all tissue samples collected form Cubb and Native breed farms were either PCR positive for CAV and IBDV coinfected with CAV while all samples were negative for IBH virus. Hematological findings showed a significant decrease (p < 0.05) in RBCs count, Hb concentration and PCV in CIA and coinfected chickens. Grossly, emaciation was characteristic in carcasses moreover, lymphoid organs were congested and atrophied beside several multifocal hemorrhagic areas in skeletal muscles accompanied with pale bone marrow. Microscopically, lesions noticed were more intense and more severe in CIA coinfection with IBDV. Generalized lymphoid cell depletion in lymphoid organs and clusters of bacterial aggregations were common. Hemopoietic elements of bone marrow showed necrosis beside extensive depletion. It could be concluded that disseminated hemorrhages mainly in skeletal muscles and viscera beside lymphoid depletion of immune organs were responsible for high mortalities in CIA infected flocks which became higher in intensity in coinfection with IBDV. Presence of bacterial colonies in various examined organs following immunosuppression. Great economic losses from concomitant and subclinical infection by CIA beside carcass condemnation so, CIA vaccination of broiler chickens is recommended