A study was conducted to determine the effect of increasing dietary cholecalciferol in deficient calcium and phosphorus broiler diets on productive performance, carcass characteristics and some tibia measurements. A total of 270 one day old Hubbard chicks were weighed and randomly allocated into a completely randomized design (five treatments, six replicate groups, nine chicks in each group). The experimental diets were as follows: (T1) control diet, was formulated according to the manual guide of Hubbard broiler chicks. (T2 to T5) tested diets were containing half of the calcium and available phosphorus requirements with extra levels of cholecalciferol 5000 (T2), 6000 (T3), 7000, (T4) and 8000 (T5) international units. The main results obtained can be summarized as follows: At 6 weeks of age, body weight and gain of birds fed either control or deficient calcium and phosphorus diets with 7000 (T4) and 8000 (T5) I.U. of cholecalciferol were significant heavier than those with 5000 (T2) or 6000 (T3) and consume less feed and gave better feed conversion ratio. The highest production efficiency factors were recorded for the control and T5 groups. Carcass characteristics (dressing % and ready to cook %) were significantly higher in birds fed control or those fed T4 and T5 diets compared with that fed T2 and T3 diets. Tibia breaking strength, tibia length and width of birds fed control or T5 diets were higher than other treatments with significant differences. It could be concluded that using the half requirements of calcium and available phosphorus in broiler diets supplemented with 8000 IU/kg cholecalciferol would  have a positive effect on the cost of production of broiler chicks, without any adverse effect on productive performance, carcass and tibia characteristics.