This study was conducted to investigate the changes in physico-chemical characteristics of beef tenderloin steak by oven roasting at different internal temperatures. 1. Cooking time required for the internal temperatures of 60, 70 and $80^{circ}$ of steaks were 15min, 23min and 28min, respectively, and standing time of cooked beef steaks were 10.5min at $60^{circ}$, 9.4min at $70^{circ}$ and 8.5min at $80^{circ}$, respectively. 2. Total losses and evaporation losses were larges in cooked steaks at $60^{circ}$ and $70^{circ}$ than that of $80^{circ}$ cooking. Total losses were 14.5% by cooking at $60^{circ}$, 23.3% at $0^{circ}$ and 26.6% at $80^{circ}$ respectively. As internal temperature of meat was increased, moisture and fats content was decreased and protein content of meat was not changed.