Pediatric interstitial lung disease comprises a diverse group of rare conditions characterized by an infiltrative process, abnormal gas exchange, and restrictive lung disease. Although the disorder is similar to its adult counterpart, its course is complicated by the continued need for lung growth and differentiation in infants and children. Knowledge about the pathogenesis, prognosis, and treatment of pediatric interstitial lung disease is limited. Investigators are focusing on defining the cellular mediators of the interstitial damage and describing the role of viral infections in and possible genetic predisposition to interstitial lung disease. Clinicians continue to define the various types of interstitial lung disease and to evaluate the roles of bronchoalveolar lavage, radiography, and biopsy in diagnosis. Together, investigators are working toward the development of specific, targeted therapy that will reduce the significant morbidity and mortality seen in pediatric interstitial lung disease.