Sixty-five has long been used to define the beginning of “old age”. Yet it is clear that the definition is arbitrary, and with continuing reductions in mortality and morbidity rates it will become increasingly inappropriate as time passes. We consider how the definition might be modified to reflect changes in life table probabilities, and how the future numbers and proportions in “old age” would be affected. In a similar manner, we consider also the redefinition of the “oldest old” from a current definition of 85 and over.
