As a component of the response to acute stress, p53 has a well established role in protecting against cancer development. However, it is now becoming clear that p53 can have a much broader role and can contribute to the development, life expectancy and overall fitness of an organism. Although the function of p53 as a tumour suppressor ensures that we can't live without it, an integrated view of p53 suggests that not all of its functions are conducive to a long and healthy life.