A: A common misconception is that toilet training during the day and night will happen at the same time. They don't. In fact, there may be several years between the ability to use the potty during the day and the ability to a) have a bladder large enough to hold urine all night and b) wake up if the body cannot hold urine all night long. So, even if your child accomplishes daytime training, keep her in diapers at night until she wakes up dry every morning for at least four weeks. Once you take away the safety net, you can either allow access to a bathroom near her room or, better yet, set up a potty seat in her room so she can go there if she needs to in the middle of the night. This is a safer solution than letting a 2- to 3-year-old have free access to roam a dark house at night.