The use of brewers' grains and orange by-products as an energy source to partially replace corn in broiler chicken feed appears to be a viable option, according to analytical results. The energy and protein values of brewers' grains justify their use, due to their usable carbohydrate content (50% DM) and nitrogenous matter (24.1% DM). The trial was conducted in the Oum Laagareb region, in the municipality of Bouteldja, El-Tarf province, in the far east of Algeria. The aim of the trial was to determine the effect of incorporating brewers' grains and orange by-products as a partial substitute for maize in the feed ration of broiler chickens on zootechnical performance. In order to determine the optimal substitution rate for brewers' grains, given that the incorporation rate for orange by-products is set at 5%. The study consists of raising 200 day-old chicks of the ISA F15 strain for 48 days, divided into four equal groups, one control and three experimental groups according to the substitution rate of brewers' grains (20%, 25% and 30%).