Don't enter duplicate items in your source list. You can use data validation
to prevent duplicates.

Suppose the list source is in the range A1:An. This is a dynamic range used
as the source for the drop down.

Select a range of cells big enough to allow for future additions. Let's
assume you select the range Range A1:A100.

Goto DataValidation
Allow: Custom
Formula:

=COUNTIF(A$1:A1,A1)<2

OK out

--
Biff
Microsoft Excel MVP


"Josh Craig" wrote in message
...
Hi,

I wanted to have a drop-down list using data validation that would let you
add extra options by entering them. In a previous post I found this
solution:

Debra Dalgleish explains dynamic range names he
http://contextures.com/xlNames01.html#Dynamic

However, there is one problem. It now displays duplicates in the drop
down
list. Is there any way to use this drop down list and a dynamic name
range
but exclude duplicates from the list?

Thanks in advance!

Josh