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The pulmonary application is a simple and convenient procedure for the patient to apply the required medication. Different application devices are available, for instance MDIs, nebulizers or dry powder inhalers. The increasing role of dry powder inhalers in the market leads to more sophisticated devices and, of course, to the improvement of the present formulations. The formulator has to evaluate the progress in the development of his product, so he needs tools for the characterisation of powders. It was the aim of the investigations described in the following to evaluate different tools and principles for powder characterisation. The solid-solid interfaces of particles are the only route for force and energy transmission. The different methods of powder characterization can boost or soften the estimated properties, because of their special way of powder handling. Many of these powder characteristics thus obtained are lin-ked to the particle size, e.g. particle size distribution, specific surface area and other sampled data. Typically the principal difficulty is the correlation of such data with the handling of one specific powder. Because these parameters are usually obtained in a static measure-ment, they do not consider the dynamic process of powder flow. This course of action is very difficult to predict or quantify, due to the diversity of affecting factors, such as shear stress, particle roughness etc. In this study, sophisticated computer-controlled powder flowability testers were investigated to show correlations to mass uniformity testing of inhalers, to the powder composition and powder handling itself.