Atopic dermatitis is a common chronic inflammatory skin disease often preceding the development of asthma and allergic disorders, such as food allergy or allergic rhinoconjunctivitis. The incidence of atopic dermatitis is increasing, and this poses a major burden on health care costs. The pathophysiology of atopic dermatitis has long remained enigmatic, but much scientific effort has been invested in elucidating the genetic background and the immunological mechanisms underlying atopic dermatitis. Pathophysiology involves a complex series of interactions between resident and infiltrating cells orchestrated by proinflammatory cytokines and chemokines. A deficiency of antimicrobial peptides might contribute to the propensity for colonization or infection by microbial organisms seen in atopic dermatitis. New management approaches have evolved form advances in our understanding of the pathophysiology of this common skin disorder. [Pediatr Allergy Respir Dis(Korea) 2006;16:189-196]