We have had this bed for a few months. It does not need a box spring to set the mattress on it. We actually have a king mattress 18" deep and it works perfect. The bed is just a little bit larger than a normal king in length but with a comforter you can hide the gap (hence why 4 stars). The bed is sturdy. It took my husband a few hours to put together. It came nicely packed. Happy with the purchase.