Diaper dermatitis is a term used to encompass a wide range of inflammatory processes that occur in the area covered by the diaper. The term "diaper dermatitis" is thus simply a description of the location of a rash. Numerous factors can be involved in the pathogenesis of dermatitis in the diaper area. These factors, including the role of the diaper, of friction and contact irritation, of urine and ammonia, of feces, of infection, and of underlying dermatologic conditions, are discussed with an emphasis on management of the rash.