Therapeutic aerosols are generated by pneumatic jet nebulizers, ultrasonic nebulizers, pressurized metered-dose inhalers, and dry powder inhalers. Some of the drug preparations used in these devices are formulated to work with specific devices. Although design improvements in aerosol devices have led to improved lung deposition, decreased oropharyngeal deposition, decreased waste of drug, greater ease of use, and lower environmental impact, optimizing the use of aerosol devices requires patient and caregiver instruction, in combination with proper device use and maintenance. Optimizing aerosol delivery requires knowledge of a number of technical details, and caregivers should stay abreast of the continuing advancement of technologies and techniques associated with aerosol delivery, especially in light of emerging devices and formulations.