It is not particle board, but a very lightweight wood. Their website explains that it's a certain type of wood from New Zealand(?) We've had ours for nearly a year and we've disassembled it once to move, it has held up very well and is quite sturdy. My son had taken to chewing the rails, and even that didn't destroy it. It could probably even be sanded and refinished.
It is real wood. . I had my doubts about ordering a crib on line but I am thoroughly impressed. I am very picky and half expected myself to send it back but I am keeping it. It is very sturdy, well built and kind of heavy. You won't be sorry if you choose to get this crib. P.S. My husband and son are both general contractors and they were impressed with the quality.