The goal of this research was to find out more about the effect of spraying garlic oil solution before incubation as natural products for egg disinfection of hatching eggs on hatching traits, post-hatch chick growth and physiological response of hatchedSinai chicks. Six hundreds of  hatching eggs were randomly separated into 4 treatments (each treatment represented with three replicates). The experimental groups were arranged as follows, the 1st group (T1) used as positive control (which eggs were fumigated with formaldehyde, the second group (T2) was sprayed with distilled water as a negative control, third group (T3) was sprayed with garlic oil solution 2ml/litter and the fourth group (T4) sprayed garlic oil solution 3 ml/litter. Results revealed that chick weight, chick shank length, chick body length and hatchability tended to be significantly higher (P<0.05) in eggs treated with garlic oil solutions when compared to control group. Embryonic mortality and egg weight loss ratio during 18 days of incubation were considerably (P0.05) lower in eggs sprayed with garlic oil solutions as compared with control group. Blood haematological parameters (RBCs, Hb, and WBC) were unaffected at hatch and at 28 days, with the exception of a modest rise in WBC count at 28 th day in response to spraying with garlic oil solution. In response to spraying garlic oil solutions, carcass contents of chicks at hatch and growth performance (body weight, feed intake, and body weight gain) of chicks during the experimental period (28 days showed significantly higher values and feed conversion improvement, while the residual yolk of chicks at hatch, , was lower than those in the control group. Comparing to control groups, garlic oil application had a substantial impact on TAOC at hatch and after 4 weeks of age. Cholesterol, triglyceride, plasma total protein, albumin, LDL and HDL were significantly differed (p < 0.05). We concluded that pre-incubation spraying of eggs with garlic oil solution as a natural disinfectant is an effective way to improve hatchability, post-hatch chick development, and physiological response of hatched Sinai chicks