A total of 100 broiler breast meat was cooked at $176^{circ}C$ to internal temperatures of either 71, 73, 75, 77, or $79^{circ}C$. Tenderness significantly decreased as internal temperatures increased. The decrease was most pronounced at $79^{circ}C$ with a 26.4% increase in Meullenet-Owens-Razor-Shear (MORS) energy compared to that at $71^{circ}C$. The toughness-temperature coefficient (TTC, change in tenderness/$1^{circ}C$ increase) was calculated to be 4.48% across the temperature ranges. Cooking loss increased constantly with the increase of internal temperatures and ranged from 15 to 27% across the range of endpoint temperatures. Poultry breast meat cooked to a higher internal temperature was in average less tender and also more variable in tenderness.