how long do i cook ribs in the oven
1 Place the ribs in the oven. 2  Cook ribs for 2-1/2 to 4 hours. 3  After about 2-1/2 hours, open a corner of one of your foil packets and test the ribs with a fork. 4  If they are tender, move on to step 5.5  Otherwise, allow them to continue to cook until they are fork tender. After about 2-1/2 hours, open a corner of one of your foil packets and test the ribs with a fork. 2  If they are tender, move on to step 5. 3  Otherwise, allow them to continue to cook until they are fork tender. 4  If in doubt, err on the side of leaving the ribs in the oven longer.