SUMMARY: A total number of 320 one day old of mixed Hubbard chicks were randomly allotted into four collections, each subdivided to two groups, 40/each. Chicks were experimented to investigate the effect of four dietary levels of crude fiber (3.5, 5.0, 6.5, and 8.0%) without or with enzymes in a factorial arrangement 4 x 2 during growing-finishing period. All the single groups were fed on the diets free enzyme, while the enzyme was added to the diet of the paired groups. The best BWG and FCR were recorded by the groups fed diets having 3.5 and 5.0% CF with enzyme supplementation (2232.94 g & 1.89) and (2116.47 & 1.90) respectively, while the worest values recorded by the groups fed diets having 8.0% CF with or without enzyme(1759.41g & 2.37) and (1748.82 g &2.51) respectively. There were no significant differences in the dressed carcass and proventriculus percentages among all the treated groups. The spleen and gizzard percentages in the birds fed diets having 8% CF with or without enzyme supplementation were significantly increased, while the liver percentages of the same groups were significantly decreased compared with the control. The results obtained concluded that addition of enzyme improved growth performance of broilers up to 6.5 % crude fiber level.