I have a nephew who was pretty big, he was still able to go in it at 2 years. (he was a big boy! lol) although eventually he was able to climb out...
he stuck one foo on the bar, and somehow, flipped/rolled out. it was kinda cute, althogh we tried not to let him do that.
actually, i think we sold it when he was sometime while he was in his 2's.. (i forget, lol) and now he is in a regular bed, in my room
lol, he still get out of that bed, he gets up, goes to my moms room, and goes to bed, (once in awhile)