Mild diaper dermatitis often occurs in children before toilet training is complete, particularly from 9 to 12 months of age, and the most common presentation is an irritant contact dermatitis. Diaper dermatitis may account for up to 25% of dermatology visits to health care providers during the first year of life. Fortunately, since the introduction of hypoallergenic, superabsorbent modern disposable diapers, the incidence and severity of irritant and allergic contact dermatitis has decreased dramatically. Diaper dermatitis broadly refers to skin disorders that occur in the diaper area, such as skin eruptions triggered by diapers, rashes exacerbated by the diaper, and other events that occur in the diaper area. A number of skin conditions that can occur anywhere on the skin may present with distinctive findings in the diaper area. The following discussion will review the most common triggers of diaper dermatitis and contact irritant dermatitis, while focusing on the skin conditions that may be associated or overlap clinically with contact dermatitis.