The current study was carried out at Maryout research station, Desert Research Center, Egypt. This experiment aimed at investigating substitution by 20% or 40% of concentrate feed mixture in Barki sheep rations by mixture (1:1) of date seeds and olive pulp that treated by 4% lime solution and incubated for 4 weeks to study their effects on growth performance, blood constituents and wool characteristics. Thirty Barki male lambs (5 months age) with average live body weight of 27.98±1.97 kg were assigned into three similar groups to be fed randomly on the experimental rations.  The tested rations were, clover hay 30% plus CFM 70% (control, C), replace 20% (T1) and 40% (T2) of CFM in control ration by the same part of mixture of treated date seeds and olive pulp. Blood serum was analyzed to determine total protein (TP), albumin, Globulin Glucose, total lipids (TL) and urea. The serum electrolytes in terms of, Sodium (Na), potassium (K), and Calcium (Ca) concentrations were analyzed. Wool samples from 10 cm² patch of mid-side position were taken from each animal. Ten staples were taken randomly from each wool sample to measure staple length. Five hundred fibers from each sample were used to calculate the average fiber diameter and its standard deviation as well as medullated fiber percentage. Results indicated that, the best feed conversion were recorded for the control group followed by Treatment 1 (T1) group and then Treatment 2 (T2) group. There was a linear decrease in the average daily gain with increasing the percentage of concentrate mixture substitution by the mixture of treated date seeds and olive pulp. Sampling time for all the experimental rations except T1 have significant (P<0.05) effect on blood glucose concentrations. The experimental rations have no significant effect on blood serum total protein concentration. However, sampling time showed significant (P<0.05) effect only for lamb group fed on ration T2. The experimental rations have no significant effect on blood urea concentration. Results showed that staple strength was higher significantly (P<0.05) in control group (21.54 N/Ktex) than T2 group (18.74 N/Ktex). The same trend was found for point of break compared to the other two groups (45.42, 34.41, and 33.16%), respectively. In conclusion, 20 or 40% of CFM could be replaced by a mixture of lime treated date seeds and olive pulp (1:1) in Barki lambs rations with slight improve for some wool characteristics and without adverse effect on some blood parameters.