Lowering dietary phosphorous (P) in poultry diets allows to reduce feed cost, environmental impact and to improve the welfare of broiler. 180 unsexed one day-old Cobb 500 were distributed equal in to 6 dietary treatments in 3 replicates of 10 chicks each. Current Ca and P recommendation of Cobb 500 broiler was considered as control (T₁) for starter and grower phase (100/100). The rest 5 dietary treatments (T_2-6) were formulated to meet (100/75-T₂), (100/50-T₃), (75/75-T₄), (75/50-T₅), (50/50-T₆) of Ca and P levels for starter and grower phase. Body weight, body weight gain, feed consumption, feed conversion ratio, carcass traits and economic efficiency were determined to evaluated and examine the effect of reduced levels Ca and P in broiler chicks diet.  The results indicated that: Growth performance showed that, all chicks fed the reduced Ca and P diets (T_2-6) didn't show any growth depression. Besides it was interestingly obtained that all reduced Ca and P diets has better body weight gain and fed conversion ratio than control. Carcass traits (carcass% and Total edible parts%) were non-significantly different for all treatment group. Economical evaluation study indicated that chicks fed on lower levels of Ca and P below the requirements enhance economic efficiency. The results of the present study showed that the current Ca and P recommendation of Cobb 500 broilers could be lower than real requirement and needs to be updated. So it was concluded that 50% reduction can be possible in dietary Ca and P level of broiler diets, and this wouldn't cause any impairment in broiler growth and carcass traits. In conclusion: The result indicated that broiler chicks fed on lower levels of Ca and P below the requirements had a positive effect on the economic efficiency of broiler chicks, without any adverse effects characteristics