In order to evaluate the phytobiotic effect of cashew (Anacardium occidentale L.) leaves powder (CLP) on growth performance, carcass traits, lymphoid organ weights and cecal lactic-acid bacteria in broilers, a total of 720 unsexed broilers of the Ross 308® genetic line were distributed according to a completely randomized design with three experimental treatments, five repetitions and 48 chickens per repetitions. The experimental treatments consisted of a basal diet (DB; T0) and DB + supplementation with 0.50 (T1) and 0.75% (T2) of CLP. At 32 days, the body weight, feed intake and feed conversion ratio were not modified (p>0.05) by the experimental groups; however, T1 increased (p<0.05) the viability compared to T0. Additionally, T2 improved (p<0.05) the carcass and leg yields, although without significant changes (p>0.05) for the other edible portions. Moreover, this natural product (A. occidentale) increased (p<0.05) the ash content and the range of the red tone and decreased (p<0.05) the L* in the breast, although moisture, fat, pH, and b* were not affected by the experimental diets (p>0.05). Similarly, T1 favored (p<0.05) the growth of green bacterial colonies with a white halo, and both treatments with CLP the total cecal acid-lactic bacteria. No significant changes were observed (p>0.05) in the relative weight of the immune organs (thymus, bursa of Fabricius, and spleen). Dietary supplementation with cashew leaves powder enhanced the viability of the batch (0.5%), some edible portions (0.75%), the breast pigmentation, and the cecal beneficial bacteria count in broilers.