This study was conducted to investigate the effects of feeding weaned lambs on diets supplemented with two levels of commercial probiotic contains a mixture of two strains of Pediococcus, Pediococcus acidilactici (1 x 106 cfu/g) and Pediococcus pentosaceus (1.3 x 106 cfu/g), with dextrose as the carrier compound on growth performance, digestibility, and blood parameters. In a growth study, 24 weaned male Saidi lambs of about 3-4 months age and an average initial live BW of 15.88±0.57 kg were randomly allotted into three groups, one group received control diet without additives, and remainders received control diet supplemented with 0.5 or 1 g probiotic/lamb/day. The experimental period lasted for 84 days. Diets were offered twice a day for ad libitum intake and contained 80% concentrate and 20% roughage. Lamb BW and feed intake were recorded. Feed conversion ratio and economical efficiency were calculated. Blood samples were collected by month. In a digestibility study, fifteen lambs initial BW = 29.72 ± 1.15 kg, age = 6.54 ± 0.32 months) were used as experimental animals in a digestion trial.  They were allocated randomly for three treatments (five per treatment) within live BW and age. Treatments contain 0, 0.5, and 1 g probiotic/lamb/day. Total DMI tended to be higher (P = 0.17) with increasing level of probiotics in the diets. Lambs fed 1 g/day of probiotic tended to have greater (P ≤ 0.10) daily gain, total gain, and a better feed conversion ratio and economical efficiency compared to the groups received control or 0.5 g probiotics/day. With the exception of either extract (EE) digestibility, all nutrients digestibility, total digestible nutrients (TDN), and digestible crude protein (DCP) values were increased with inclusion probiotic in the diets. Probiotics supplementation did not change serum constituents of total protein, albumin, globulin, and glucose levels, however blood urea and cholesterol concentrations were decreased (P ≤ 01) with increasing level of probiotic in the diet.  In conclusion, supplementation of probiotic at high level of 1 g/day in weaned lamb diets may be have appositive effect on nutrients digestibility which result in improve growth performance, feed conversion, economic efficiency, and animal health through decrease cholesterol concentration in the blood.