This study was conducted to investigate the relationship between corticosterone hormone in the blood of local Iraqi white chicken mothers and the sexual ratio of the hatching chicks. A field experiment located at the Poultry Research Station, Livestock Department, Agricultural Research Department, Ministry of Agriculture for the period from 16 of September 2018 to 25 of December 2018. One hundred and forty birds of Iraqi local chicken mothers (100 females+ 40 males) at the age of 28 weeks were provided from the poultry research station. The birds were raised in individual cages and distributed sequentially to the cages after the numbering of the females. Data were recorded in three periods, each period was of 28 days, and then the general average of each studied character was calculated. Blood was withdrawn at the end of each period to measure the concentration of corticosterone in maternal blood, and then the birds were distributed on the basis of hormone concentration to three groups: low, medium, and high to compare the performance of mothers. The results showed a significant difference in the concentration of corticosterone hormone in the blood of mothers (Ng/100 ml) according to the level of the class, percentage of hatching chicks and the secondary and primary sex ratios. A linear relationship was observed between the studied traits and corticosterone concentration levels through calculation the regression and correlation as well as the adoption of the method of estimating the results of the prediction to reach the best predictive values that bring closer to reality. It can be concluded that the second period of the experiment was the …