This experiment was conducted to evaluate the effect of Bifidobacterium adolescentis isolated from broiler crops on villus high and crypts depth of jejunum tissues and relative internal organs weight of broiler chicks (Ross 308). Chicks were subdivided into four treatments: the first treatment was considered as control, and other three treatments were treated by inoculating the chicks with 0.25 ml once weekly for (7 week) with normal saline (second treatment); enrofloxacin (third treatment; and liquid culture containing 7.1 × 108 colony forming unit/ml from B. adolescentis (fourth treatment). The results showed that there was a significant increase (P≤0.01) in the villus high in bifidobacteria treatment compared with control and antibiotic treatment, and significant increases in crypt depth of Lieberkuhn in bifidobacteria treatment compared with antibiotic treatment at 1st week of age. At the 2nd week bifidobacteria treatment significantly increases (P> 0.01) in crypt depth of Lieberkuhn and villus high compared with all treatments, and the same significant increases was happened at the 4th treatment in bifidobacterai treatment compared with all treatment in villus high and but only with antibiotic and normal saline treatment in crypt depth of Lieberkuhn. The relative weight of internal organs was not affected by bifidobacterai treatment except the percentage of duodenum weight to its long at the 2nd week in the bifidobacterai treatment compared with normal saline treatment.