Bedwetting occurs more commonly at night after a child has been toilet trained independently from 2 to 4 years of age. Initially, the frequency of bedwetting may be 2-3 times a week, but then it becomes less frequent and stops occurring altogether around the age of 5. Some children continue to wet the bed at night after the age of 5. When bedwetting occurs only during sleep, it is called nocturnal enuresis. The age of bladder maturation varies from person to person, with boys being later than girls, and there is often a family history of bedwetting. Although the cause of bedwetting is not fully elucidated, it may be related to the child’s different developmental rhythms (neurological, muscular, and whether the sensation of a full bladder is subconsciously suppressed at night). Bedwetting is generally not associated with any other physical or psychological disorder. Some children are born with smaller bladders that are more likely to fill up, and some studies have suggested that some children do not produce enough antidiuretic hormone (ADH), which is secreted by the pituitary gland during sleep, causing the kidneys to produce less urine so that the bladder does not fill up. If the “brain-bladder” nighttime communication is delayed, or if the bladder is too small to hold the urine overnight, the child will continue to wet the bed. Bedwetting will improve as the child grows and develops. In addition, it is important to pay attention to whether the bedwetting is caused by disease, such as urinary tract infections, developmental abnormalities, etc. Routine urinalysis, sacrococcygeal x-ray, urinary ultrasound, etc. can be done.