Can you post some examples of what you have and where the data is not
sorting correctly?

If the birthdays have been entered as dd/mm, then Excel will take this
as meaning a date and will assume the current year. Formatting might
allow you to hide the year, but it is still there if those are correct
Excel dates. You might have some dates of birth with the correct year,
but as those are hidden then it might appear that the dates have been
sorted incorrectly. Format the cells as dd/mm/yyyy (temporarily) to
see what is really in those cells.

Another problem might be that you have entered dd/mm as a text value,
and these will sort in a different way. They will be unaffected by
changing the format to dd/mm/yy.

Hope this helps.

Pete

On Jan 12, 6:33*pm, 4most wrote:
Xcel 2003. *Similar to an earlier thread. *I have verified that all cells are
formatted as numbers, dates 00/00. *Some of the items in the column will
sort, but some will not. *I have cleared the print area; I have Unhid the
superfluous columns, thinking I might have to sort the birthdates and THEN
hide. *No joy.