I agree with Julie's post. Bad habits are hard to break and many times we don't realize we are helping a bad habit develop when it's happening. One suggestion is to evaluate your son's daytime habits regarding napping. It may very well be your son needs a more consistent daytime nap routine or napping schedule. Little ones go through so many cognitive and physiological changes that it's hard to narrow down what could be going on, especially when they are new at walking, still getting teeth, still new to solids, etc. Many times a more structured napping schedule helps the nighttime sleep fall into or back into place. I've noticed as much with my son who is now 24 months that if I don't stick to a consistent routine and time frame, everything gets affected. You may have to resort to staying in his room, telling him you'll stay a little while next to his crib on the floor and then you have to go to your bed too. Slowly but surely you can help him acquire good habits and want to stay in his crib. Another suggestion is to consider how bright his room might be at 4:30-5am. I discovered the time change influences the brightness of my son's room when he was put to bed and when he awoke and this was despite having vertical blinds. I used posterboard to block out the light until I was able to buy some fabric and ask my mom to help make some curtains. I would highly recommend considering this option in addition to anything else you might do. I used two layers of fabric: a dark green on the room side and a light beige on the window side. The key is to be sure the curtain rod and curtains extend beyond the window casing otherwise sunlight comes in around the edges. This worked wonders and helped a great deal in sending the message that darkness signaled sleep. I also put some little low-glow nightlights in two sockets so if I do need to respond to something, I can see what I'm doing. My son is not afraid of the dark at all and he was 14 months old when I got the curtains up in his room. I'm sure you'll get lots of great advice from moms. All the best to you and your little one.