The ideal internal temperature for pork tenderloin when you take it out of the oven is 145°F. This temperature ensures that the pork is safe to eat and will be juicy and tender. It is important to use a meat thermometer to check the internal temperature of the pork. Insert the thermometer into the thickest part of the meat, not touching bone, fat, or stuffing, to get the most accurate reading. Once the pork reaches 145°F, remove it from the oven and let it rest for about 5 minutes before slicing. This allows the juices to redistribute throughout the meat, resulting in a more flavorful and tender pork tenderloin.