This study was designed to investigate the effects of oxytetracycline on the amount of calcium and phosphorus of blood and bone tissue density in broiler chickens. For this purpose, 72 day-old Ross chicks of, 308 strain in a completely randomized design in two groups: the control group (without dietary antibiotic) and the treatment group (with a diet containing oxytetracycline 50%, 3 gr per kg of diet) with 6 replicates in the same environmental conditions and management were studied for 42 days. In this experiment, the diameter of femoral shaft and ratio of various tissues of the femur and skull were studied. Blood parameters included calcium and phosphorus. In the group treated with oxytetracycline, femur shaft diameter was significantly decreased with the addition of drug to diet (