There is still a lack of knowledge in the field of aerosol therapy in children, particularly in young children. The amount of drug delivered from a commercially available inhalation device that reaches the lungs of children is generally low. The choice of an optimal combination of delivery device and drug formulation based on individual patient related factors is crucial. Aerosols with a small MMAD and a narrow GSD are required for a sufficient inhalation therapy in early childhood. The development of combinations of delivery devices and drug formulations fulfilling the requirements for an efficient inhalation therapy in young children is likely to increase the therapeutical options in this age group.