The effective and efficient delivery of aerosol medications involves physician factors (correct diagnosis and correct prescription of appropriate medications), device factors, and patient factors. For nearly all infants and children, the authors administer asthma medications either using a pMDI with a valved holding chamber or a DPI. Regardless of the device chosen, parent and patient education is critical for the appropriate use of the device, and frequent reinforcement of the educational message will often improve adherence and correct use.