Trail was conducted to study the effect of in ovo administration of nano encapsulated and dietary inclusion of thyme oil on broiler growth performance and carcass traits. Egg injected at 18 day of incubation with 0.03ml/egg with nano thyme oil (T3) other group injected with normalsterilesaline as positive control group (T2) and negative control group with not injected (T1). After hatching the chicks allotted to feeding trial with 80mg/kg of feed with Nano encapsulated thyme oil to study their effect on growth performance and carcass traits in relation to control non treated groups. The result showed that there was a significant(P < 0.05) increase in body weight and body weight gain, significant (P < 0.05) improvement in feed consumption and feed conversion ratio, while no significant effect on carcass traits in in ovo injected and dietary Nano thyme oil relative to control group.