Hyperbranched polymers are by now an established class of polymeric materials and can be considered as highly functional specialty products. It is verified that they offer the chance for the development of new products but at the same time they present a challenge due to their complex branched structure. Examples out of a broad variety of structures are discussed as well as several possible applications. It is demonstrated that the structure of hyperbranched polymers with all different structural units can be full), clarified which allows the determination of the degree of branching, verification of side reactions as well as considerations regarding reaction mechanism and kinetics of the branching process. By modification of the end groups the properties of hyperbranched polymers, e.g. glass transition temperature, solubility and miscibility, melt viscosity, as well as surface properties, are significantly determined and define mainly possible applications. These applications range from blend components to processing aids and coating formulations as well as thin film applications e.g. in sensories. (C) 2003 Academie des sciences. Published by Editions scientifiques et medicales Elsevier SAS. All rights reserved.