We had the same problem recently with our 2 1/2 year old. We went on vacation in December and we all slept in the same room for a week, so as soon as we got back, he wanted to sleep in our room every night. I tried all the suggestions about putting him back in his room every time he got up, talking to him about being a good sleeper, rewarding him for a good night (which never happend)closing the door if he was crying, and altogether making a big deal out of it. Nothing worked and none of us were getting any sleep, so I finally gave up. If he wanted to come in our room in the middle of the night and sleep on the floor, we let him. We compromised, sort of. The rules were: he had to go to bed in his own room at bedtime, he could sleep on our floor, but not in our bed, and he was not allowed to wake us up. He would bring his blankie and pillow and make himself comfortable on the floor - he did this every night at about 2 a.m. for almost three weeks, but in the end this approach really worked. After a few weeks, he was back to sleeping in his own room through the night. Once I stopped fighting with him about it, it was no longer a big deal. It's like, as long as he knows the option is there if he feels like he needs to come in our room, he knows it is his decision, and it is no longer a power struggle. Occasionally I still get up in the morning and find him on the floor next to our bed, but that doesn't bother me. I am okay with it since we still get a good night's sleep. I don't know if this will work for you or not, but I know all the "book stuff" did not work for us.