High-resolution CT in children remains a technically challenging procedure, both to perform optimally and to interpret correctly. Although much remains to be learned about its optimal application, it is apparent that often confusing or nonspecific chest radiographs are clarified and a much clearer understanding is being gained about the diagnosis and evolution of both common and unusual pediatric lung diseases. As new therapies become available for these disorders, and CT becomes faster and easier to perform, it will become increasingly used not only for more accurate diagnosis but also for better evaluation of effects of therapy.