Perfecto!
This was easy! Not sure why so many people are asking for this when the solution is fairly simple!
STEP 1:
Went to the EDIT feature for my current theme.
STEP 2:
Clicked on the “Main Index Template (index.php) in the right hand column.
STEP 3:
Find “The Loop” which always starts with something like:
<?php if (have_posts()) : ?>
or
<?php if ( have_posts() ) : while ( have_posts() ) : the_post(); ?>
STEP 4:
Added this line JUST BEFORE “The Loop”:
<?php query_posts($query_string . ‘&cat=-19’); ?>
(my excluded Category was 19, for more than one category use: -3,-19 (separate your categories with commas!)
That’s it. Thanks!