Selenium is a trace element essential in animal nutrition and exerts multiple actions related to enhance animal production, fertility, immune response and antioxidant defense system of chickens. The aim of the present study is investigating the benefit effects of selenium nanoparticles (SEN) in-ovo injection on productive performance, express stimulate antioxidant defense system and immune response of hatched chicks.  A total of 210 broiler breeder eggs ( Habbard Star-Bro) were divided into three in-ovo injection treatment groups,( 0, 5 and 10 ppm SEN) and incubated. Hatchability traits , productive performance,  biochemical profile, antioxidant status and immune response of hatched chicks were estimated. Results indicated significant increase in HDLcholesterol, T3, GSR, GSH, IGA, IGM and IGG as affected by in-ovo inoculated SEN levels. However feed conversion ratio, triglycerides and MDA significantly decreased by in-ovo treatments. No significant alternations were recorded in hatched chicks weight, feed intake, body weight, body weight gain, carcass characteristics, and serum levels of protein fractions, cholesterol, LDL- cholesterol, ALT, AST, ALP, uric acid, creatinine and glucose in in-ovo treated groups compared with the control one. It is summarized that, in-ovo inoculation of different levels of SEN can improve feed conversion ratio, lipid profile, antioxidants status and immunity of  broiler hatched chicks.