In a helper column adjacent to your set of data, you can enter a
formula like:

=MOD(ROW(),3)

and copy this down. This will return values of 0, 1, and 2 down the
column. If you apply an autofilter to this column you can select which
of these values you want to display - suppose you choose 0. Then you
can click on the first visible cell, hold down <SHIFT, press <End
once followed by <down, and then release <SHIFT. Without clicking on
another cell, use the pull-down on the filter to select All, and then
you will have every third cell highlighted.

Hope this helps.

Pete

On Nov 21, 6:51 pm, jme951 wrote:
Is there a formula or an easy way to select/highlight every third cell in a
very long column of data?
--
Thanks,
Jamie