In the current study, biochemical parameters, oxidative status, lymphoid organs and immune response for broilers challenged with aflatoxins (AF) were examined to determine the preventive efficacy of food supplementation with tomato waste powder (TWP). A total of 300 Ross (308) broiler chicks one-day old were randomly distributed in five treatments and six replicate (ten birds per replicate); feed and water were provided ad libitum throughout the 35 days' experiment. Treatments were as follows: (T1) A basal diet containing neither AF nor TWP (positive control) and (T2) a basal diet containing 100 µg/kg AFB1 (Negative control). The other three treatment groups were supplemented with TWP at 2.5, 5.0 and 7.5 g/kg plus the 100 µg/kg AF. The results showed that Aflatoxicosis decreased total protein, albumin, and globulin concentrations and greater liver and kidney functions in broiler chickens as compared with the AFB1- group (P<0.05). As compared with the T2 group (Negative control), inclusion of 5 and 7.5 g TWP/kg increased serum total protein, albumin, and globulin and the TWP additive decreased liver and kidney functions of broiler chickens comparing with the control group. Lymphoid organs (thymus and bursa) relative weight, and immune response to NDV and IBD were decreased and increases were observed in interleukin 2 (IL-2), IL-6, and interferon γ (IFN-γ) in the T2 group, whereas spleen relative weight, heterophil percentage and heterophil-to-lymphocyte ratio were increased (P<0.05). Aflatoxicosis increased blood and hepatic malondialdehyde concentration, whereas TAC, SOD and GSH were decreased (P<0.05) in blood and hepatic.  As compared with the T2 group (Negative control), the levels of TWP (5 and 7.5 g TWP/kg) improved liver and serum oxidative status concentration (P<0.05). Moreover, interleukin 2 (IL-2), IL-6, and interferon γ (IFN-γ) significantly (P<0.05) diminished in TWP + AFB1 groups when compared with the AFB1 group. It can be concluded that the levels of TWP (5 and 7.5 g TWP/kg) are capable to decrease the negative impact of AFB1 on broiler chickens' biochemical parameters, lymphoid organs, oxidative status, and immune response.