The effects of feeding Arbor Acres Plus broiler breeders on diets containing different levels of prednisolone on the primary sex ratio of the offspring were studied. A total number of 132 healthy, vaccinated, Arbor Acres Plus chickens at 59 weeks of age were selected, individually weighed, leg banded and then distributed into four treatments. Each treatment contained three replicates of 11 birds each (1 male + 10 females). Birds in groups 1 to 4 were provided with basal diet supplemented with prednisolone at the levels of 0, 5, 10 and 20 mg/kg diet, respectively, over a period of 45 days. Eggs were collected for duration of 30 days and were incubated at temperature of 37.8ᵒC and 65% relative humidity. The hatching chicks were feather sexed at 0 day of age. The results showed that birds fed diets containing Prednisolone at the levels of 5 and 20 mg prednisolone/kg diet had significantly (P<0.05) higher percentage of males in their offspring compared to the control group. Prednisolone supplementation had no effects on most of blood parameters under study except that it significantly increased plasma albumin concentrations. From these results, it could be concluded that prednisolone supplementation at the levels of 5 and 20 mg prednisolone/kg diet altered the sex ratio in the offspring of broiler breeders (Arbor-Acres).