Medication for the treatment of asthma and chronic obstructive pulmonary disease should be given locally by inhalation. There is, however, no such thing as an ideal inhaler, or ‘Idealhaler’, which has all desired properties with no drawbacks. In this short review, we have compared the relative merits of the two most commonly used dry powder inhalers – Turbuhaler® and Diskus™. Clinical effect is related to the amount of inhaled drug that reaches the lungs, and this in turn depends on the amount of fine particles generated at inhalation. Turbuhaler® is more than twice as effective as Diskus™ at generating fine particles, and the higher lung deposition with Turbuhaler® is accompanied by a lower variability in lung deposition. Compared with Diskus™, the lung deposition with Turbuhaler® is affected less by factors such as humidity.