How long does raw ground beef last after being frozen and thawed? Ground beef that has been defrosted in the fridge can be kept for an additional 1 to 2 days in the refrigerator before cooking; ground beef that was thawed in the microwave or in cold water should be cooked immediately. How long does ground beef last in the fridge once it is cooked? Cooked ground beef will usually stay good for 3 to 4 days in the fridge and 4 months in the freezer.