Effect of using two by-products (sugar beet pulp and date seeds) untreated or biologically treated with different combinations of fungi, bacteria and yeast in sheep feeding on digestibility coefficients, rumen fermentations and rumen microbes, and blood biochemicals was investigated. The study included laboratory experiment, digestibility trail and in vitro gas production. Digestibility trail included six experiments: T (1): Concentrate feed mixture (CFM) + berseem hay (BH) (Control). T (2): CFM contained untreated sugar beet pulp (SBP) and date seeds (DS) + BH. T (3): CFM contained SBP and DS treated with T. virideand S. cerevisiae + BH. T (4): CFM contained SBP and DS treated with T. viride and C. cellulasea + BH. T (5): CFM contained SBP and DS treated with C.cellulasea and S. cerevisiae+ BH. T (6): CFM contained SBP and DS treated with T. viride with C. cellulasea and S. cerevisiae+ BH. Biological combination treatments improved chemical analysis and fiber constituents, while reduced anti-nutritional factors of DS. T6, T4, T3 and T5 increased (P<0.05) digestibility coefficients, nutritive values, nitrogen utilization,   microbial protein, rumen fermentations parameters and microbes numbers, gas production at different incubations times and blood serum total proteins and albumin were improved (P<0.05) in T6, T4, T3 and T5, respectively, compared with control and untreated groups. Control group showed higher values than untreated group. Inclusion of sugar beet pulp and date seeds untreated or treated with biological treatments to replace a part of 70% of common concentrate feed mixture had remarkable improved influence on sheep feeding.