any ideas.

this works fine in category.php <?php echo category_description(the_category_id()); ?>

but it doesn't operate in single.php, only the category id turns up not the description.

any ideas, how to accomplish this?

thanks ahead of time

edited:

the_category_id() 

continues to be deprecated. This will work rather.

$category = get_the_category();
echo category_description($category[0]->cat_ID);