OBJECTIVE: This study examined the effects of a nutrient matrix with or without phytase on the performance of broiler chicken. METHODS: A total of 2,000 day-old Ross 308 broiler chickens were assigned to 5 dietary treatments, with 10 broilers per replicate and 40 replicates per treatment. The experimental diets included 1. CON: A corn and soybean meal (SBM)-basal diet without phytase. 2, NC1: A corn-SBM-based diet with reduced nutrients, specifically 0.13% less phosphorus, 40 kcal/kg less metabolizable energy (ME), and 0.30% less crude protein (CP), without phytase. 3, NC1+PHYT: NC1+500 FTU/kg phytase. 4, NC2: Another corn-SBM-based diet with greater nutrient reductions, including 0.16% less phosphorus, 55 kcal/kg less ME, and 0.45% less CP, without phytase. 5, NC2+PHYT: NC2+1,000 FTU/kg phytase. RESULTS: In the pre-starter and overall phase, feed conversion ratio (FCR) was higher in NC2 and NC2+PHYT. In the starter phase, body weight gain (BWG) was lower in NC2 and NC2+PHYT. In the grower phases, BWG was lower in NC2, while FCR was higher. At d28, the digestibility of ash was higher in NC1+PHYT, while the digestibility of Ca and phosphorus were higher in NC1+PHYT and NC2+PHYT. At day 42, the digestibility of ash, Ca, and phosphorus were higher in NC1+PHYT and NC2+PHYT. The level of tibia ash was lower in NC2. The level of myo-inositol was lower in NC2 at d28, while the level of myo-inositol at d42 was lower in NC1 and NC2. CONCLUSION: We concluded NC1+PHYT showed a higher growth performance comparable to CON, as against the lower performance observed in NC2, NC2+PHYT, and NC1.