This study was carried out to evaluate the effect of dietary supplementation of the commercial probiotics (Bacillus amyloliquefaciens) (BA), an enzyme mixture containing xylanase, amylase and protease (XAP) enzymes, and their combination (BA+XAP) on growth performance, carcass characteristics, some blood biochemical parameters, and intestinal microbiota of broiler chicks. A total number of 320 one-day-old unsexed broiler chicks (Ross) with an average body weight of 43.65±0.19 g were assigned to 4 dietary treatments (80 chicks/treatment), each containing 4 replicates (20 chicks/replicate). The dietary treatments were as follows: control) fed basal diet without supplementation, T1) fed basal diet supplemented with BA probiotic at level 15 g / kg diet, T2) fed basal diet supplemented with XAP enzymes at level 400mg / kg diet, and T3) fed basal diet supplemented with AB and XAP at levels 15 g and 400mg /kg diet, respectively. The results indicated that dietary supplementation of BA probiotic significantly increased body weight, body weight gain, dressing weight and breast weight, and improved feed conversion ratio and performance index of broiler chicks compared with the other treatments. Also, the dietary supplementation of XAP enzymes or the mixture of AB and XAP significantly increased body weight and body weight gain of broiler chicks compared with control but did not effect on feed conversion ratio and performance index of broiler chicks. Feed consumption for all treated chicks was significantly higher than control. The highest plasma total proteins level was found in T2 followed by the mixture T3 and control, respectively, and the lowest level was found in T1. Also, T2 had the highest albumin level followed by T1. The highest plasma globulin level was found in T3 compared with T1 and control groups, followed by T2 compared with T1 group. T1 and T2 had the highest Triglyceride level compared with the other treatments. In conclusion, supplementing diets of broiler chickens with BA probiotics, XAP enzymes and their combination displayed positive effects on growth performance, immune status, and intestinal microbiota; the BA treatment showed the most pronounced results