Background: Although the use of non-starch polysaccharide-degrading enzymes (NSPases) in corn, oat, rye, barley or wheat-based broiler diets has already been researched for some years, little attention has been given to the mixture of wheat and barley, as basic raw materials for broiler feed. Objective: To evaluate the effect of different inclusion levels of commercial NSP enzymes in corn or in the mixture of wheat/barley-based diets on growth performance, carcass quality and blood parameters of broilers. Methods: Three hundred 1 d-old male broiler chicks (Ross-308) were fed two basal diets (corn and a wheat/barley-based diets), two commercial feed enzymes (Kemin® and Rovabio®), and two enzyme levels (0.025 and 0.05%) in a 2×2×2 factorial arrangement, from 1 to 42 d of age. Results: Overall, birds fed corn-based diets with or without enzyme supplementation consumed more feed (p < 0.05) over the entire experiment, experienced higher weight gain (p < 0.05) and lower feed conversion ratio (FCR; p < 0.05) when compared with wheat/barley-based diet. Notwithstanding, FCR did not improve in birds fed corn-based diets with enzymes, while gain and FCR improved (p < 0.05) feeding wheat/barley-based diets with 0.05% NSPases. Economical traits of carcass were not affected (p > 0.05) by the treatments, while blood biochemistry parameters, such as glucose, VLDL and HDL changed (p < 0.05) when enzymes were supplied. Conclusion: Our results show bio-efficacy of feeding xylanases and glucanases in wheat/barley based-poultry diets, rich in NSPases, which could translate into economic benefits.