You can use data validation to do this.

Suppose the range of interest is A1:A5
Select the range A1:A5
Goto the menu DataValidation
Allow: Custom
Formula: =COUNTIF(A$1:A$5,A1)<2
OK out

Whenever you attempt to enter a duplicate value you'll get a popup error
message.

Biff

"J." wrote in message
...
I'm trying to set up a spreadsheet and I have a list where I would like
items
picked only once.
Once that item has been picked, is it possible for it not to reappear in
the
list in all the remaining cells in the range?