Our study was carried out to evaluate the efficacy of probiotic (BIOPELLET – S ®) and synbiotic (MT – TRON ®) on some hematological parameters in broilers either in healthy state or experimentally challenged with E. coli (O78). 150 day old cobb chicks were divided into 6 equal treatments (A-F) 25 chicks per each and reared for 6 weeks. Group (A) control non-treated. Groups (B & E) were received probiotic (1 g/liter drinking water). Groups (C & F) were received synbiotic (0.5 ml/liter drinking water). Groups (D, E and F) were inoculated by intranasal route with 0.5ml of PBS (phosphate buffer saline) contains 4 X 10⁶ CFU E.coli O78 organism /ml at 3 weeks old. Hematological results revealed normocytic normochromic anemia in group challenged with E. coli. While, groups treated with probiotic and synbiotic showed no changes in hemogram. A significant leukocytosis, lymphocytosis and heteropenia were recorded in probiotic and synbiotic treated groups compared with group challenged with E. coli and that not infected.