Plywood, terrible quality. The first desk I received had nails poking out and had clearly been left in the snow or rain at some point - although the box was left inside my apartment building, it was soaked through. This meant that the plywood was damaged and it literally fell apart as I was trying to build it. Separate from the defect, the drawers are incredibly narrow and shallow. They're very impractical and don't fit files. I asked for a replacement and a partial refund, but was told that any refund would mean I wouldn't be able to get another replacement. The customer service agent was honest and said there was a big chance they'd mess it up again. Not worth the price at all.