This study was conducted to investigate the effect of in ovo injection of vitamin D3 during different embryogenesis periods on post hatch productive performance, some blood parameters, bone growth and jejunum and tibia bone histology of Hubbard chicks.  A total number of 500 eggs with average weight of 65 g were obtained from a commercial broiler breeder flock (Hubbard) at 55 weeks of age. Eggs were divided into five groups of 100 eggs in four replicates, 25 eggs each. The first one was served as negative control group (un-injected), while the second and third groups were used as sham control which were injected with (0.1 ml sterile water\egg) into air cell at day 7and 14, respectively (SE7, SE14). The Fourth and Fifth groups were injected with a dose of 0.1 ml vit.D3 (Containing 500 IU) into air cell at day 7 and 14 of incubation period respectively (DE7, DE14).  The present findings revealed that chicks hatched from eggs injected with vit. D3 has significantly better productive performance (higher LBW and BWG, less FI and better FCR) than control and sham groups. Plasma level of PTH, Ca, P, ALK-P and ACP were significantly increased with in ovo injection with vit. D3. Also, Tibia weight, length and width were significantly increased for the in ovo injected with vit.D3. Femur weight, length and width were insignificantly increased for the in ovo injection with vit.D3. Shank length was significantly increased for the in ovo injection with vit.D3, while shank width was insignificantly increased compared with the control and sham groups. Furthermore, the histological structure of bone was enhanced with in ovo injection with vit. D3 either at 7 or 14 days of incubation period. In conclusion from the present study shows that in ovo injection with a dose of 0.1 ml vit.D3 (Containing 500 IU) in Hubbard broiler chicks at 7^th or 14^th day of incubation period enhanced productive performance, blood parameters, bone development and histological structure.