The present study aimed at evaluating the effect of two strains of probiotics (Bacillus subtilis PB6 and Bacillus Cereus var. toyoi) on selected indicators of the antioxidant status and immune responses of broilers before and after challenge with Salmonella enterica subsp. Typhimurium (S. typhimurium). Birds were distributed into the following five treatments: negative control (CTL−); negative control+S. typhimurium (CTL+); antibiotic+S. typhimurium, (AB); Toyocerin®+S. typhimurium (TOYO); and CloSTAT TM + S. typhimurium (CLOS). Birds in all treatments, except for CTL−, were orally challenged with 3 x10 9 CFUS. typhimurium at 16 days of age. The results showed that total antioxidant capacity (TAC), superoxide dismutase activity (SOD), and hydrogen peroxide (H 2 O 2 ) values were similar among all groups. The antibody titers against S. typhimurium and Newcastle disease (ND) were not affected by the treatments (p>0.05). However, S. typhimurium and ND titers were influenced by the interaction between week and treatment (p<0.01, p<0.05, respectively) and by week (p<0.001, p<0.001, respectively). In conclusion, S. typhimurium challenge had an impact on anti-Salmonella and NC titers. Both probiotics did not affect the broilers' antioxidant capacity.