This study was carried out to evaluate the impact of dietary supplementation of probiotic (Diamond XP™) T1 or prebiotic (BioBoost^TM) T2 on nutrient digestibility, rumen fermentation characteristics, productive performance and economic efficiency of Barki lambs. Lambs in control group offered a concentrate feed mixture (CFM) and clover hay without supplementation while, lambs in treatment (T1) and treatment (T2) were fed CFM supplemented with probiotic or prebiotic at rate of 10 g/ head/ day, respectively. Nine barki male sheep (47kg ± 2.5) were used for running metabolism trail. The animals were allocated into three equal groups. Three ruminally cannulated ewes (45 kg ± 3.2) were used to study the rumen liquor parameter, while growth performance trails were carried out with twenty four growing male Barki lambs (27.5 kg ± 0.75) used to determine the growth performance, feed conversion and economic efficiency.The obtained results could be summarized as follow: Animals given ration supplemented with probiotic recorded the highest values of (p<0.05) digestibility and nitrogen utilization followed by animals given ration supplemented with prebiotic, however those fed control ration  had the lowest values. The same trend was observed with TDN and DCP values.No significant (p<0.05) differences among rations in ruminal pH values, were recorded while total volatile fatty acids (VFA's) concentration and microbial protein synthesis had significantly (p<0.05) increased with probiotic supplement. The control ration recorded the highest ruminal NH3-N concentration. A positive impact of probiotics (DFM) and prebiotic supplementation on nutrient intake, feed conversion ratio and economic efficiency have been recorded. It could be concluded that feeding lambs on rations supplemented with either probiotic (DFM) or prebiotic at 10 g/h/d has beneficial effects on rumen parameters, digestibility coefficients, growth performance and economic efficiency of growing Barki lambs.