In the Data Validation dialog box, when you enter the Source, either use
a named range (=MyList), or an absolute reference to cells on the active
worksheet (=$G$1:$G$20)

There are instructions he
http://www.contextures.com/xlDataVal01.html

Martin wrote:
How do I create a drop down list to use for a whole column of cells, allowing
the same set of values to be used for what will be hundrededs of rows of data
over time? Also, when I thought I had created a drop down list, the allowed
entries disappeared after being chosen just once!


--
Debra Dalgleish
Contextures
www.contextures.com/tiptech.html
Blog: http://blog.contextures.com