I believe the shelf life is ten years, but they are still good after that. I seem to recall a pair of blokes who wanted to travel around the world using pedal power alone. They cycled on land and had a pedal powered boat made up to cross water with. They were given a job lot of out of date rations by the Army and it didn't seem to do them any harm. Remeber, you get a lot of calories from a 24 hour ration pack, it is designed that way due to the nature of working in a job where you have to run about with heavy loads shooting people! For their size, they are ideal, even if some of the items are horrible!