A study was undertaken to evaluate the effect of prebiotic, probiotic and synbiotic supplementation on intestinal microflora and histomorphology of broilers. One-day-old Avian 48 chicks (n=100) were randomly assigned to 4 treatments (25 birds/treatment) for 6 week experiment. Each treatment consisted of 3 replicates (two replicate of 8 birds and one with 9 birds). Treatment groups were as follow: 1. Basal diet (control); 2. Basal diet plus Mannan- Oligosaccharide (MOS) at levels of 2 g /kg of the starter diets and 0.5 g/kg of the grower diets); 3. Basal diet plus probiotic (3 g/kg diet, Saccharomyces cerevisiae); and 4. Basal diet plus the combination of pre and probiotics (synbiotic). On d 21 and 42, 3 birds per treatment were sacrificed to evaluate gut morphology and microbiology. Duodenum, jejunum, ileum, and cecum microflora composition and intestinal histomorphology were determined. The final body weight (BW), weight gain, feed conversion efficiency were significantly (p<0.05) higher in probiotic and synbiotic supplemented broilers compared with the control and prebiotic groups. Concentrations of bacteria belonging to Lactobacillus spp. in the duodenum and jejunum digesta at d 42 were significantly (P <0.05) higher in prebiotic supplemented broilers compared with the control and synbiotic treatments. However, synbiotic supplementation maintaining populations of unprofitable or potential pathogens (E. coli) at relatively low levels (numerically) in the small intestinal and cecal digesta. In addition, the total aerobes and coliform colony count were not significantly affected by any of the dietary treatment. Morphology data for the small intestine showed that synbiotic supplemented broilers had significantly higher (p < 0.05) villus height in the duodenum, jejunum, ileum in comparison with the other treatments. The crypt depths were numerically (p > 0.05) decreased in duodenum and ileum in synbiotic supplemented broilers. In addition, the age had significant effect on intestinal histomorphology. Moreover, the interaction between dietary treatment and age did not affect (p > 0.05) any of the intestinal histomorphological parameters.