This study was carried out to determine the effect of the supplementation of enzyme and probiotic to broiler feeds based on barley and wheat on broiler performance, dressing percentage, the small intestinal length and weight, liver and abdominal fat weights, intestinal viscosity and the percentage of sticky droppings. In this experiment, 600 one - day - old Hubbard broiler chicks were used. This study was performed on four treatment groups, each containing 150 chicks. One of the groups was the control group and the others were the experimental groups. Each treatment group was divided into 6 replicates of 25 chicks. The chicks were fed with broiler starter diet between days 1 and 21, broiler grower diet between days 22 and 35, and broiler finisher diet between days 36 and 42. While the control group was fed a diet without supplemented diet enzyme (l kg avizyme/ton), probiotic (0.23 kg fastrack/ton) and enzyme + probiotic (1 kg avizyme + 0.23 kg fastrack/ton) were added to the diets of the experimental groups respectively. The experimental period was 42 days. Live weight gain and feed consumption of all the groups were determined every week during the experiment. Nine male and nine female chickens from each group were slaughtered at the end of the experiment. The weights and percentages of the hot and cold carcass, the liver, abdominal fat and small intestine weights and the small intestine length were determined. Digesta viscosity was examined in 12 chickens from each treatment groups on day 25. At the end of the experiment, the addition of enzyme and enzyme + probiotic to the diet significantly increased body weight gain (P<0.001) and improved feed conversion ratio (P<0.001). Enzyme with/without probiotic supplementation significantly decreased intestinal viscosity (P<0.01) and sticky droppings (P<0.05), increased hot and cold carcass percentages and liver weight (P<0.001) and decreased abdominal fat weight (P<0.05) in all the experimental groups. The effect of enzyme and probiotics on small intestine weight was found to be significant (P<0.001). The values of the small intestine weight were 17.95 and 9.47% higher for groups fed enzyme and enzyme + probiotic and 1.41% lower for the group fed probiotic than those of the control group. It was concluded that the addition of enzymes and probiotics individually or in combination to diets based on barley and wheat improves the performance of broilers and reduces intestine viscosity and sticky droppings.