The aim of this study was to investigate the effects of in ovo injection of vitamin A on some blood parameters in broiler chickens at 7 and 35 day of age. Six hundred fertile eggs of Hubbard broiler breeder were divided into 4 groups. One group served as a control (T0) while the other groups were injected with 100 (T1), 150 (T2) and 200 I.U (T3) vitamin A at day zero before placing in the hatching machine. After hatching, serum lipid profile and liver function enzymes were determined. Results showed no significant differences between control and treated groups at 7 day of age in the form of GOT, GPT, ALP, cholesterol, triglyceride, HDL and VLDL whereas LDL was significantly higher in treated groups compared to control. At day 35, GOT, GPT and ALP were significantly lower in treated groups compared to control. Furthermore, serum cholesterol and LDL was significantly lower in T3 compared to control. No significant difference was found in triglycerides and VLDL between treated and control groups. Data suggested that, in ovo injection of vitamin A can significantly reduce serum GOT, GPT, ALP, cholesterol, LDL and increased HDL at day 35 in broiler chickens.