Are you eventually going into his room when he does this? I was once told by a wonderful pediatrician that if you go into his room, he will continue the behavior until you come into his room. If you wait 45 minutes until you go to his room, he'll cry for 45 minutes the next night or longer since he knows that you will eventually come back. My daughter used to scream until she puked. I didn't know what to do. So, after talking to my doctor, he said as awful as it sounds, to go ahead and let her puke and after she falls asleep, go in and clean it up. Believe it or not, this is exactly what I did and three days later, I had a daughter who as soon as I laid her in her crib, would fall asleep without a fight. She just realized that I wasn't coming back no matter what, so she threw in the towel. Sometimes we do things that we feel awful about, but you have to remember that in situations like this, if you are going back into that room after you have told your child it's time for bed, then you are giving the control over to them by going back in because at that point, they're supposed to be sleeping. So, let the child cry it out, let him scream, let him kick on the door, whatever he feels he needs to do, but if you never, not once, react to it, then he will realize he's wasting energy.