The present study was carried out at the Department of Poultry and Fish production, Faculty of Agriculture, Shibin El-Kom, Menoufia University. The experiment was extended from Oct. 2020 to Nov. 2020, in order to investigate the relationship between in ovo injected Vitamin D₃ and its effect on chicken performance, hatchability, mortality, some blood properties and immunity. - The studied traits were as follow: Body weights at different ages, feed consumption (FC) (kg per bird/cycle), feed conversion ratio FCR, titration and calculation of antibody titers and, blood characteristics and liver enzymes. The results indicated that all traits were significantly affected by injected by VD₃ levels.