Are atheists Humanists?
Not necessarily. A great number of atheists subscribe to some humanistic beliefs. (for a better idea of what secular humanism is about, go here.) Most atheists are concerned with reason, ethics, and the pursuit of objective truth, as means to advancing the human race. Other atheists will tell you up front how little they care. If you’re an atheist looking for a more specific “label” for your beliefs, and you’re not a complete misanthrope, then secular humanism probably has something to offer you.