Hi Scott

Create named ranges corresponding to each of your 6 digit numbers, each
containing the list of valid entries.
If your first validation is in A1, set the validation in B1 to be List
Source =INDIRECT(A1)
For more help look here
http://www.contextures.com/xlDataVal02.html
--

Regards
Roger Govier

"Scott K" <Scott wrote in message
...
I need to be able to dynamically set the valid range of selectable values
in
a second cell based on the value entered in the first cell. Specifically,
when my users select a six-digit account number from a drop-down box
(using
DataValidation), I need the cell to the right to restrict its possible
range
of selectable values based on what account number was chosen.

I am using Excel 2003 and I have a good bit of experience using VBA if
that's the tool I should be using.